Public History Review Vol. 28, 2021 © 2021 by the author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License (https:// creativecommons.org/licenses/ by/4.0/), allowing third parties to copy and redistribute the material in any medium or format and to remix, transform, and build upon the material for any purpose, even commercially, provided the original work is properly cited and states its license. Citation: Piper, A. J. 2021. Alana Jayne Piper, What is Digital History? (Cambridge: Polity Press, 2021). Pp338. Paper $39.99. Public History Review, 28, 1–2. http://dx.doi. org/10.5130/phrj.v28i0.7745 ISSN 1833-4989 | Published by UTS ePRESS | https://epress. lib.uts.edu.au/journals/index. php/phrj BOOK REVIEW Alana Jayne Piper, What is Digital History? (Cambridge: Polity Press, 2021). Pp338. Paper $39.99. Reviewed by Alana Jayne Piper Australian Centre for Public History University of Technology Sydney DOI: http://dx.doi.org/10.5130/phrj.v28i0.7745 Digital history is a field that escapes easy definition due to its incorporation of an ever- growing variety of methods, disciplines and endeavours. However, this slim volume – part of Polity’s What is History series – provides a solid introduction to the terrain as it lies at the start of the third decade of the twenty-first century. As Salmi comments in the book’s opening, the digital ‘tends to emphasize the present tense’ (p1). This means that any work attempting to capture the state of the field risks potential obsolescence in the face of the rapid development of new tools, projects and approaches. Salmi’s work though not only charts digital history’s past and present, but looks to the future of the field in ways that mean it is likely to remain a useful reference point for some years to come. The book begins with a brief but useful overview of the rise of digital history, with Salmi pointing out that computerised historical analysis date back to the early 1960s. Discussions of early digital humanities projects from the 1970s-1990s appear throughout the book, offering fascinating insights into how early adopters of technologies influenced their later development and take-up. The book as a whole, however, makes clear how pivotal the last twenty years has been in accelerating the expansion of humanities computing. The first chapter examines one of the most common areas of digital history, which even historians who do not identify as digital practitioners now interact with on a daily basis: digital sources. Salmi focuses in particular on the problems that accompany such sources, from biases in the archives selected for conversion to digital formats to the ephemeral nature of the born- digital sources of our own age. These are methodological challenges relevant to historians as a whole, as well as to those working in collecting institutions. The second chapter considers textuality and how distant reading has the power to transform our understanding not only of sources but the practice of history itself. If the fundamental task of a historian is to read intensively and extensively in order to identify patterns and changes DECLARATION OF CONFLICTING INTEREST The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. FUNDING The author(s) received no financial support for the research, authorship, and/or publication of this article. 1 https://creativecommons.org/licenses/by/4.0/ https://creativecommons.org/licenses/by/4.0/ https://creativecommons.org/licenses/by/4.0/ http://dx.doi.org/10.5130/phrj.v28i0.7745 http://dx.doi.org/10.5130/phrj.v28i0.7745 https://epress.lib.uts.edu.au/journals/index.php/phrj https://epress.lib.uts.edu.au/journals/index.php/phrj https://epress.lib.uts.edu.au/journals/index.php/phrj http://dx.doi.org/10.5130/phrj.v28i0.7745 across sources and time, then machine-reading can now allow us to do this at an unprecedented scale. Salmi concurs with other scholars, though, that such approaches are best balanced alongside traditional close reading approaches. This is followed by a chapter investigating visuality as a method of presenting and understanding history, from the increasing availability of visual sources online to groundbreaking techniques in spatio-temporal mapping and data visualisation. The final two chapters are brief. The fourth chapter outlines the various disciplines that have contributed to the growth of digital history, and the challenges such interdisciplinarity presents for researchers when it comes to developing shared resources. The last chapter will be of particular interest to public historians as it concentrates on the use of digital tools for presenting the past to different audiences. For novices to digital history, the book offers a highly accessible introduction to the methods and problems of computerised historical analysis. It traverses digital history projects from across several continents and a number of useful tools and platforms, from social network visualisation generator Gephi to the user-friendly workshop site The Programming Historian. For existing digital history practitioners, the book will provide a useful reference point, especially for current challenges faced by the field. Some of the most pressing ones identified by Salmi include: the inaccessibility of digitised sources kept behind paywalls, and the issues this presents to increasing efforts at data linkage; lack of visibility of sources that have been digitised with preservation, not searchability, in mind; and the availability of digital research materials dictating historical research agendas and thereby limiting the questions asked. Although not mentioned by Salmi, this last concern must be a particularly pressing one in light of how COVID-19 is likely to prompt increased reliance on digital sources by historians. 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