Cohen is the co-writer of "Digital History: A Guide to Gathering, Preserving, and Presenting the Past on the Web" (University of Pennsylvania Press, 2005), and author of "Equations from God: Pure Mathematics and Victorian Faith" (Johns Hopkins University Press, 2007). He has published articles and book chapters on the history of mathematics and religion, the teaching of history, and the future of history in a digital age in journals such as the Journal of American History, the Chronicle of Higher Education and Rethinking History. He is an inaugural recipient of the American Council of Learned Societies’ Digital Innovation Fellowship.

At the Center for History and New Media he has co-directed, among other projects, the September 11 Digital Archive and Echo, and have developed software for scholars, teachers, and students, including the popular Zotero research tool.

He received his bachelor's degree from Princeton, master's from Harvard, and doctorate from Yale.