College and Research Libraries


B y D A V I D J U D S O N H A Y K I N 

Book Classification and the Problem 
of Change 

Mr. Haykin is editor of the Decimal 

Classification. 

TH E R E IS A P A R A D O X i n t h e a t t i t u d e o f l i b r a r i a n s t o w a r d the classification of 
their book collections. O n the one h a n d , 

they point to the inadequacies of the sys-

tem they e m p l o y and b l i t h e l y — p e r h a p s one 

should say, i n n o c e n t l y — p r o c e e d to m a k e 

changes in the system, ostensibly either in 

o r d e r to c o r r e c t f l a w s in the system or to 

a d a p t it to the " l o c a l s i t u a t i o n . " O n the 

other h a n d , they are a w a r e o f — i n d e e d , they 

point t o — t h e cost of c h a n g e and appear 

satisfied if the system p r o v i d e s a place, a n y 

place, f o r a topic w i t h o u t r e f e r e n c e to the 

u n i t y and consistency of the system. B e -

cause this p a r a d o x exists, it is necessary to 

e x a m i n e the v a r i o u s f a c t o r s in the p r o b l e m 

of c h a n g e as they a f f e c t libraries. I t is ex-

pected that this e x a m i n a t i o n w i l l p r o v i d e 

the basis f o r m o r e r a t i o n a l solutions of the 

p r o b l e m . 

M o d e r n systems of classification f o r li-

b r a r y m a t e r i a l s are based p r i m a r i l y on sub-

j e c t relationships, l a r g e l y d i s r e g a r d i n g such 

considerations as l a n g u a g e , f o r m a t , c h r o n o l -

o g y ( d a t e of publicaion, age o r period c o v -

ered, o b s o l e s c e n c e ) , or r e l e g a t i n g t h e m to 

a secondary o r d e r . T h e obvious assump-

tion t h a t u n d e r l i e s s u b j e c t relationships is 

that users of the books on the shelves, both 

the l i b r a r y ' s p u b l i c and the l i b r a r y ' s s t a f f , 

are best served by a s u b j e c t a r r a n g e m e n t . 

O t h e r w i s e , libraries c o u l d find j u s t i f i c a t i o n 

f o r a r r a n g e m e n t by a u t h o r . L a w libraries, 

f o r e x a m p l e , sometimes a r r a n g e treatises by 

a u t h o r , so t h a t books on diverse s u b j e c t s 

stand t o g e t h e r on the shelves and books on 

the same topic are scattered. T h e u n d e r l y -

i n g assumption here is t h a t the user of the 

l i b r a r y w o u l d n o t be a w a r e o f , o r con-

c e r n e d w i t h , books d e a l i n g w i t h s u b j e c t s 

related to the one he is c o n c e r n e d w i t h at 

the m o m e n t and t h a t his needs w o u l d be 

satisfied by r e s o r t i n g to the a l p h a b e t i c a l ar-

r a n g e m e n t on the shelves by a u t h o r or to 

the c a t a l o g u n d e r the a p p r o p r i a t e s u b j e c t 

h e a d i n g . M a n y libraries, n o t a b l y p u b l i c li-

braries, m a k e their p r i m a r y a r r a n g e m e n t by 

l a n g u a g e , t h a t is, a l l the G e r m a n books to-

g e t h e r , the F r e n c h books t o g e t h e r , and so 

on. H o w e v e r , the books in each l a n g u a g e 

are then a r r a n g e d by s u b j e c t f o l l o w i n g the 

o r d e r of the system of classification by sub-

j e c t . I n o r d e r to m a k e the most e c o n o m i c a l 

use of space libraries f r e q u e n t l y g r o u p t h e i r 

books by size, s h e l v i n g o c t a v o v o l u m e s separ-

a t e l y , then quartos, folios and e x t r a o r d i -

n a r i l y l a r g e books, each as a separate g r o u p . 

H e r e , too, h o w e v e r , each g r o u p is v i r t u a l l y 

a l w a y s a r r a n g e d a c c o r d i n g to the s u b j e c t 

classification. L a r g e l y , then, m o d e r n libra-

ries deem it best to a r r a n g e their books by 

s u b j e c t , the g e n e r a l assumption b e i n g t h a t a 

l i b r a r y f o l l o w i n g the open-shelf policy or 

n e a r l y all A m e r i c a n p u b l i c and school libra-

ries, the user of the l i b r a r y m a y either find 

the book he desires a m o n g o t h e r books on the 

same s u b j e c t or, f a i l i n g to find it, w o u l d be 

satisfied w i t h a n o t h e r book on the same sub-

j e c t . F o r the r e f e r e n c e and r e a d e r - a d v i s o r y 

staff of the l i b r a r y a s u b j e c t a r r a n g e m e n t is 

considered a definite a d v a n t a g e , since it o f t e n 

370 COLLEGE AND RESEARCH LIBRARIES 



enables t h e m to find several books on the 

same s u b j e c t of w h i c h one m a y c o n t a i n pre-

cisely the i n f o r m a t i o n s o u g h t . T o a casual 

user of the shelves the s u b j e c t a r r a n g e m e n t 

also has a suggestive v a l u e ; t h a t is, it leads 

the user to an interest in related topics, 

w h i c h in a s u b j e c t a r r a n g e m e n t w o u l d be 

c o n t i g u o u s or near to the s u b j e c t s o u g h t . 

A n i m p o r t a n t i m p l i c a t i o n in a n y classifi-

cation based on s u b j e c t a r r a n g e m e n t is t h a t 

f a m i l i a r i t y w i t h a s u b j e c t implies on the 

p a r t of the user of the l i b r a r y some sense 

of the s t r u c t u r e of the s u b j e c t m a t t e r and 

of the relationships of topics w i t h i n the sub-

j e c t . T h u s , f o r e x a m p l e , it is assumed t h a t 

the user w h o seeks a book on income t a x 

w o u l d be a w a r e t h a t t a x a t i o n is an e l e m e n t 

of public finance, and that it is associated 

w i t h customs and t a r i f f , the public debt, 

g o v e r n m e n t bonds, and the l i k e ; so t h a t , if 

he e n c o u n t e r e d books on a n y of these topics, 

he w o u l d expect to find the m a t e r i a l he 

seeks n e a r t h e m . I f there w e r e no such 

assumption, l i b r a r y needs w o u l d be satisfied 

by a sequence of u n r e l a t e d topics, the se-

quence b e i n g a r r a n g e d p u r e l y a r b i t r a r i l y in 

the o r d e r in w h i c h they i n i t i a l l y come u p 

f o r consideration, or a l p h a b e t i c a l l y , o r by 

a n y other method o t h e r than one based on 

s u b j e c t relationships. T o equip a n y such 

a r r a n g e m e n t w i t h a system of n o t a t i o n w o u l d 

be a r e l a t i v e l y simple m a t t e r . 

A user of the open shelves of a p a r t i c u l a r 

l i b r a r y w o u l d become f a m i l i a r w i t h the lo-

cation of books on the topics of his interest 

and r e t u r n to them w i t h o u t d i f f i c u l t y . Y e t 

the s u g g e s t i v e v a l u e of a t r u e s u b j e c t ar-

r a n g e m e n t w o u l d be lost and a n y s h i f t i n g of 

the books m a d e necessary by the g r o w t h of 

the c o l l e c t i o n or f o r a d m i n i s t r a t i v e reasons 

w o u l d require the user to l e a r n a n e w loca-

tion f o r his topic. 

V i r t u a l l y all m a k e r s of s u b j e c t classifica-

tions h a v e r e c o g n i z e d the v a l u e of the com-

m o n use of a single system. M e l v i l D e w e y 

r e c o g n i z e d this f r o m the v e r y b e g i n n i n g . 

A l t h o u g h the L i b r a r y of C o n g r e s s classifica-

tion w a s devised solely w i t h the needs of 

the L i b r a r y of C o n g r e s s in m i n d , its use 

by a considerable n u m b e r of libraries has 

increased its v a l u e to other libraries, n o t 

only because the class n u m b e r s on L i b r a r y 

of C o n g r e s s c a t a l o g cards eliminates most 

of the cost of c l a s s i f y i n g , b u t i n t e r l i b r a r y 

loans and other m u t u a l l i b r a r y services are 

f a c i l i t a t e d and i m p r o v e d . T h e u n i v e r s a l 

use of the D e w e y D e c i m a l C l a s s i f i c a t i o n in 

public, school, and u n i v e r s i t y and c o l l e g e 

libraries has e n c o u r a g e d schools, colleges, 

and universities to o f f e r e l e m e n t a r y instruc-

tion in the system, p r e s u m a b l y because it 

helps the students in the use of the books 

on the shelves and because of its c o n t i n u i n g 

help in the use of other libraries. T h e s e 

considerations h a v e a b e a r i n g as w e l l on 

c e n t r a l i z e d classification and the p r o b l e m of 

c h a n g e as w i l l be b r o u g h t o u t l a t e r . 

S u b j e c t classifications are the r u l e in 

m o d e r n libraries and are considered h e l p f u l 

to the r e f e r e n c e and r e a d e r - a d v i s o r y s t a f f , 

the h a b i t u a l users of the l i b r a r y , in sub-

sequent use of o t h e r libraries, and in inter-

l i b r a r y relations and services. T h i s is the 

raison d'etre of s u b j e c t classification, aside 

f r o m a n y sense of orderliness or c o n f o r m i t y 

to a system of k n o w l e d g e w h i c h they im-

p a r t . L i b r a r i e s can h a r d l y avoid s u b j e c t 

classification f o r their open-shelf o r even 

limited-access collections. T h e p r o b l e m of 

change m u s t , t h e r e f o r e , in the first instance 

be considered in this c o n t e x t . O n l y insofar 

as circumstances diminish the v a l u e of sub-

j e c t classification can other f a c t o r s , no 

m a t t e r h o w i m p o r t a n t , become the d o m i n a n t 

considerations. 

T h e discovery of n e w f a c t s and the shed-

d i n g of n e w l i g h t on old f a c t s tend to a f f e c t 

the o r g a n i z a t i o n of k n o w l e d g e , hence the 

s t r u c t u r e of book classification. I f s u b j e c t 

classification has v a l u e , it derives it p r i m a r i l y 

f r o m its c o n t i n u i n g relationship to the or-

g a n i z a t i o n of k n o w l e d g e . T h o s e w h o h a v e 

OCTOBER, 1955 
40 7 



devoted a n y time to d e s c r i b i n g and c r i t i c i z -

i n g e x i s t i n g s u b j e c t classification h a v e in-

v a r i a b l y f o u n d f a u l t w i t h the f a i l u r e s of 

l o g i c in their s t r u c t u r e and the l a g b e t w e e n 

the schedules and a d v a n c i n g k n o w l e d g e . 

A n y o n e f a m i l i a r w i t h the D e w e y D e c i m a l 

C l a s s i f i c a t i o n has heard criticism of the or-

g a n i z a t i o n of the 100 class ( P h i l o s o p h y ) , 

of the separation of the 800 class f r o m the 

400 class, of the l a c k of a d e q u a t e provision 

f o r topics in m o d e r n physics, f o r the exten-

sive l i t e r a t u r e of sociology, f o r m o d e r n 

p s y c h o l o g y . T h e clear i m p l i c a t i o n of this 

criticism is t h a t the system is expected not 

o n l y to e x p a n d b u t to c o r r e c t w h a t is no 

l o n g e r v a l i d in the l i g h t of increased k n o w l -

edge. I n f a c t , the editors t h r o u g h the years 

have been u r g e d by libraries not o n l y to ex-

pand p a r t i c u l a r parts of the classification 

not deemed by the libraries sufficiently de-

tajed f o r their needs, but also, and fre-

q u e n t l y , to c o r r e c t w h a t they deemed to be 

errors, w h e r e a s in m a n y instances they w e r e 

not o u t of line w i t h the state of k n o w l e d g e 

years ago, b u t in the l i g h t of present-day 

k n o w l e d g e w e r e no l o n g e r v a l i d . E v e n 

the separation of 400 f r o m 800 and of 300 

f r o m 900 can be explained on the basis of 

the B a c o n i a n system or an accepted o r d e r 

of the sciences at the time the D e w e y D e c i -

m a l C l a s s i f i c a t i o n came i n t o b e i n g ; y e t 

h a r d l y a n y b o d y w o u l d find the separation 

reasonable n o w . 

T h e history of the D e w e y D e c i m a l 

C l a s s i f i c a t i o n , t h r o u g h its successive edi-

tions, is n o t by a n y means f r e e of c h a n g e . 

I t is true t h a t most of its d e v e l o p m e n t w a s 

by accretion, y e t c h a n g e s in v a r y i n g degree, 

other than expansions, h a v e been m a d e 

f r o m the v e r y b e g i n n i n g , even if w e leave 

the first, o b v i o u s l y t e n t a t i v e , edition out of 

consideration. A s e x a m p l e s of c h a n g e s 

f r o m the 2nd edition t h r o u g h the 1 2 t h one 

m i g h t cite the f o l l o w i n g : 1 ) 3 3 3 . 9 m e a n t 

fisheries ( o b v i o u s l y in connection w i t h its 

economic aspects) in the 2 n d t h r o u g h the 

9 t h edition, and w a t e r r i g h t s t h e r e a f t e r ; 2 ) 

M o r m o n i s m , w h i c h w a s 298 t h r o u g h e i g h t 

successive editions and since the 10th has 

been 2 8 9 ; 3 ) g e n e r a l E u r o p e a n history, the 

periods of w h i c h t h r o u g h the 9 t h edition 

w e r e assigned the n u m b e r s 9 4 0 . 1 - 9 4 0 . 9 and 

in the 10th w e r e c o n t r a c t e d to 9 4 0 . 1 - 9 4 0 . 2 

in o r d e r to p r o v i d e shorter n u m b e r s f o r the 

W a r ( 9 4 0 . 3 - . 4 ) and 940.5-.9 f o r succeed-

i n g p e r i o d s ; 4 ) p s y c h o l o g y , w h i c h has been 

classified d i c h o t o m o u s l y in 1 3 0 and 1 5 0 

t h r o u g h the 1 2 t h edition, w a s p r o v i d e d in 

the 13 th w i t h an " a l t e r n a t i v expansion 

based on present-day lines of t h o t " ; and 5 ) 

systematic b o t a n y , w h i c h t h r o u g h f i f t e e n edi-

tions has, c o n t r a r y to the g e n e r a l principle 

of s t r u c t u r e in classification, proceeded f r o m 

the most c o m p l e x to the simplest, w a s in 

the 1 4 t h edition p r o v i d e d w i t h an a l t e r n a -

tive a b r i d g e d f r o m the U n i v e r s a l D e c i m a l 

C l a s s i f i c a t i o n and e m b r a c i n g , in the reverse 

o r d e r , a l l systematic b o t a n y u n d e r 582 

r a t h e r t h a n 5 8 2 - 5 8 9 as in previous editions. 

T h e c h a n g e f r o m 9 4 0 . 1 - . 9 to 9 4 0 . 1 - . 4 , it 

m i g h t be noted, i n v o l v e d considerable n u m -

bers of books in all libraries since the n u m -

bers c o v e r e d the g e n e r a l history of E u r o p e 

f r o m the f a l l of the R o m a n E m p i r e to date. 

T h o s e libraries w h i c h decided to keep the 

D e w e y D e c i m a l C l a s s i f i c a t i o n w e r e obliged 

to reclassify their books on this s u b j e c t . In 

a l l libraries there w e r e considerable n u m b e r s 

classified in 940/. 1 t h r o u g h 9 4 0 . 9 w h i c h , 

by the change in the 10th edition, had to be 

reclassified. O t h e r w i s e , each l i b r a r y had 

to d e v e l o p on its o w n the classification f o r 

the history of E u r o p e b e g i n n i n g w i t h the 

F i r s t W o r l d W a r . I f it did not do so, it 

w o u l d to some e x t e n t lose the benefit de-

rived f r o m the use of a c o m m o n classifica-

tion and c o u l d n o t m a k e direct use of the 

D e c i m a l C l a s s i f i c a t i o n n u m b e r s on L i b r a r y 

of C o n g r e s s cards. I t is doubtless t r u e that 

some libraries at the present time are still 

using editions a n t e c e d e n t to the 1 0 t h . I f , 

h o w e v e r , a sound and up-to-date classifica-

372 COLLEGE AND RESEARCH LIBRARIES 



tion is of v a l u e to libraries, these libraries 

are behind the procession and f a i l to reap 

the f u l l benefit of a c o m m o n classification 

and of the c o o p e r a t i v e and c e n t r a l i z e d w o r k 

of the L i b r a r y of C o n g r e s s , the H . W . W i l -

son C o m p a n y , and the A m e r i c a n L i b r a r y 

A s s o c i a t i o n . 

T h e r e is no d e n y i n g o r m i n i m i z i n g the 

economic f a c t o r in classification. A sub-

s t a n t i a l p a r t of the cost of p r e p a r i n g l i b r a r y 

m a t e r i a l s f o r use is c h a r g e a b l e to classifica-

tion. I t is this f a c t , a m o n g others, w h i c h 

pointed the w a y to c o o p e r a t i v e and cen-

t r a l i z e d classification. M e l v i l D e w e y him-

self r e c o g n i z e d the economic w a s t e i n v o l v e d 

in separate classification of a book by a 

n u m b e r of libraries, even aside f r o m the f a c t 

that c o o p e r a t i v e classification o f f e r s the 

means of s e c u r i n g g r e a t e r s u b j e c t com-

petence f o r the task. A n d even m o r e than 

the cost of o r i g i n a l classification, libraries 

m u s t look w i t h a c r i t i c a l eye at the probable 

cost of reclassification. M a n y a l i b r a r y 

a d m i n i s t r a t o r , burdened w i t h the necessity 

of k e e p i n g d o w n the cost of p r e p a r i n g ma-

terials f o r use in o r d e r to m a i n t a i n basic 

l i b r a r y services, is w i l l i n g to assume t h a t a 

book once classified should remain classified 

regardless of the i m p o r t a n c e of s u b j e c t 

classification and of the v a l i d i t y of the class 

n u m b e r s . T h e s e a d m i n i s t r a t o r s f r e q u e n t l y 

decide to accept w i t h o u t questioning, and 

c e r t a i n l y w i t h o u t s t u d y or i n v e s t i g a t i o n , 

class n u m b e r s provided by c e n t r a l i z e d , co-

operative classification services. If s u b j e c t 

classification and the v a l i d i t y of n u m b e r s 

are r e a l l y i m p o r t a n t , this a t t i t u d e on the 

p a r t of a d m i n i s t r a t o r s is to be deplored, y e t 

the m o t i v e s behind the a t t i t u d e are real and 

sometimes inescapable. W e m u s t r e c o g n i z e 

t h a t such a d m i n i s t r a t o r s are w i l l i n g to toler-

ate a c e r t a i n m a r g i n of e r r o r and to accept 

less t h a n the f u l l effectiveness of class n u m -

bers. T h e p r o b l e m of change is met by them 

head on and their decisions accept the con-

sequences. 

H o w e v e r , our p a r t i c u l a r concern, as in-

dicated at the b e g i n n i n g of this paper, is 

the a t t i t u d e of l i b r a r i a n s — a d m i n i s t r a t o r s 

of libraries, a d m i n i s t r a t o r s of so-called tech-

nical processes, and p r a c t i c i n g c a t a l o g e r s 

a l i k e — w h o insist on the v a l u e s of classifica-

tion, on the one hand r e j e c t o u t r i g h t c h a n g e s 

in the system, y e t on the other hand i n d u l g e 

in less v a l i d and g e n e r a l l y less j u s t i f i a b l e 

c h a n g e . I t is an u n d e n i a b l e f a c t t h a t m a n y 

libraries a m o n g those w h i c h are seriously 

concerned w i t h classification deviate f r o m 

official, published versions of the systems 

they ostensibly f o l l o w and d e f e n d against 

c h a n g e . I t w o u l d be difficult to find a 

single l i b r a r y of substantial size u s i n g the 

D e w e y D e c i m a l C l a s s i f i c a t i o n w h i c h has 

not deviated in one or t w o i m p o r t a n t w a y s 

f r o m the published schedules. P e r h a p s the 

commonest deviation is the use by l o c a l de-

cision of a n u m b e r in a p a r t i c u l a r sense 

other t h a n t h a t o b v i o u s l y intended by the 

D e w e y D e c i m a l C l a s s i f i c a t i o n . A l i b r a r y 

w h i c h , f o r e x a m p l e , omits the use of 327 

f o r f o r e i g n relations and instead broadens 

3 4 1 . 2 to include it, c l e a r l y deviates f r o m 

the published schedules. So does a l i b r a r y 

w h i c h develops an expansion of its o w n in 

o r d e r to c o n c e n t r a t e u n d e r one g r o u p of 

n u m b e r s m a t e r i a l s f o r w h i c h provision 

c l e a r l y exists e l s e w h e r e in the schedules. 

W h e t h e r by the use of n u m b e r s in a sense 

not intended by the schedules or expansions 

l o c a l l y developed w h i c h are o u t of line, 

l o g i c a l l y or s t r u c t u r a l l y , w i t h the published 

schedules, the libraries w h i c h d e v i a t e f o r 

w h a t e v e r reason lose the v a l u e s of l i b r a r y 

cooperation w h i c h result f r o m u s i n g a com-

m o n classification and f r o m c e n t r a l i z e d 

classification. T h e r e is v a l u e to the reader 

in b e i n g able to find in t w o libraries the 

same s u b j e c t m a t t e r u n d e r the same n u m b e r . 

T h e r e is a similar t e m p o r a r y v a l u e to n e w 

m e m b e r s of the staff. T h e user w h o w a s 

i n t r o d u c e d to the classification by his school 

l i b r a r y is l i k e l y to be disconcerted in n o t 

OCTOBER, 1955 
40 7 



being able to find in the p u b l i c l i b r a r y a 

book f o r the s u b j e c t of w h i c h he learned 

the c o r r e c t class n u m b e r in school. T h e li-

b r a r y w h i c h does not d e v i a t e can f r e e l y use 

the class n u m b e r s assigned c e n t r a l l y and 

thus e f f e c t a s a v i n g in the cost of classifica-

tion, even aside f r o m the l i k e l i h o o d t h a t 

n u m b e r s are assigned c e n t r a l l y m o r e o f t e n 

by classifiers of special s u b j e c t competence. 

O n e m u s t not leave c o m p l e t e l y o u t of con-

sideration the f a c t t h a t l o c a l l y d e v e l o p e d 

expansions require c o n t i n u e d l o c a l e d i t i n g 

and expansion and are thus a d d e d c h a r g e 

in the cost of c l a s s i f y i n g the l i b r a r y ' s col-

lections. 

W h e t h e r d e v i a t i o n s are desirable or not 

and in spite of the cost, it m u s t be remem-

bered t h a t no l i b r a r y is l e g a l l y or m o r a l l y 

bound to adhere f a i t h f u l l y to the published 

schedules. T h a t they have d e v i a t e d so gen-

e r a l l y is itself evidence t h a t they w e r e f r e e to 

m a k e the decision. H o w e v e r g r e a t l y devia-

tion m a y be d e p l o r e d , it is in f a c t w i d e l y 

practiced. I t c a n n o t be r e d u c e d or b r o u g h t 

to a stop e x c e p t by a u n i v e r s a l r e c o g n i t i o n 

and a c k n o w l e d g e m e n t of the v a l u e of ad-

h e r i n g to the i n t e n t of the editors of the 

published schedules, regardless of differences 

of opinion in r e g a r d to the v a l i d i t y or use-

ableness of the n u m b e r s . T h i s is not the 

expression of a hope or e x p e c t a t i o n , b u t 

m e r e l y the s t a t e m e n t of the c o n d i t i o n u n d e r 

w h i c h libraries u s i n g the D e w e y D e c i m a l 

C l a s s i f i c a t i o n can reasonably e x p e c t the re-

d u c t i o n or e l i m i n a t i o n by the editors of 

c h a n g e s in the schedules. 

So l o n g , h o w e v e r , as the purposes and 

uses of a s u b j e c t classification are r e c o g n i z e d 

and accepted, the editors m u s t h e w to the 

line and a t t e m p t to achieve a classification 

w h i c h is, as f a r as possible, in accord w i t h 

present day k n o w l e d g e . T h e y m u s t of 

necessity t e m p e r v a l i d i t y w i t h e x p e d i e n c y 

and a v o i d changes w h i c h w o u l d necessitate 

large-scale reclassification on the p a r t of 

libraries t h a t do f o l l o w the schedules f a i t h -

f u l l y and e m p l o y a m i n i m u m of deviations. 

T h i s still leaves o t h e r libraries c o m p l e t e l y 

f r e e n o t to c h a n g e their present practice and 

to c o n t i n u e to d e v i a t e and m a k e their o w n 

expansions. T h e m a c h i n e r y f o r l i m i t i n g 

c h a n g e is in existence in a l l libraries t h a t 

h a v e e m p l o y e d deviations. I t lies in the 

m a r g i n a l a n n o t a t i o n s and separate instruc-

tions w h i c h they h a v e m a d e f o r their cata-

l o g e r s to f o l l o w . H a v i n g used this m e t h o d 

b e f o r e , there is n o t h i n g these libraries need 

to do beyond i n d i c a t i n g , f o l l o w i n g e v e r y 

c h a n g e in the revised schedules, the o l d e r 

n u m b e r w h i c h they w o u l d use instead. In-

e v i t a b l y libraries h a v e a n n o t a t e d their copies 

of the 1 4 t h e d i t i o n ; i n e v i t a b l y the D e c i m a l 

C l a s s i f i c a t i o n Section a n n o t a t e d its copies 

of the 1 4 t h and 1 5 t h editions to s h o w the 

v a r i a t i o n s w h i c h are to be used on the L i -

b r a r y of C o n g r e s s cards. O n e of the 

l a r g e s t p u b l i c libraries in the c o u n t r y has 

used the D e w e y D e c i m a l C l a s s i f i c a t i o n se-

l e c t i v e l y r e g a r d l e s s of e d i t i o n ; this l i b r a r y 

i n e v i t a b l y had to g o d o w n the line and select 

f r o m both the 1 4 t h and 1 5 t h editions the 

n u m b e r s it chose to use. W h e r e the c h a n g e s 

are deemed i m p o r t a n t e n o u g h f o r a l i b r a r y ' s 

purposes, it f o l l o w s t h a t the necessary ex-

pense w i l l be i n c u r r e d and the c h a n g e made. 

I n public and school libraries, w h o s e col-

lections do n o t o r d i n a r i l y serve the purpose 

of research, there is a v a l u a b l e b y - p r o d u c t 

of r e c l a s s i f i c a t i o n : it is the time f o r w e e d -

ing-out of the c o l l e c t i o n s o u t - o f - d a t e and 

o t h e r w i s e unused books. 

I n s u m : the v a l u e of s u b j e c t classification 

is g e n e r a l l y r e c o g n i z e d ; it derives its v a l u e 

in p a r t f r o m the v a l i d i t y of its o r g a n i z a t i o n 

and in p a r t f r o m its c o m m o n use by a n u m -

ber of l i b r a r i e s ; in spite of the i m p o r t a n c e 

of c o m m o n use, libraries f r e q u e n t l y d e v i a t e 

f r o m the accepted, published f o r m of the 

c l a s s i f i c a t i o n ; the c h a n g e s w h i c h a classifica-

tion m u s t u n d e r g o to retain its v a l i d i t y 

t h r o u g h the g r o w t h of k n o w l e d g e m a y be 

treated by libraries as they t r e a t the e x i s t i n g 

c o m m o n classification, t h a t is by a c c e p t i n g 

the c h a n g e s on a selective basis. 

374 COLLEGE AND RESEARCH LIBRARIES