The book industry is an important social, cultural, and economic institution whose records deserve to be preserved for the public good. Books.Files was an exploratory project funded by the Andrew W. Mellon Foundation aimed at assessing the archival value of digital assets in the contemporary publishing industry for stakeholders in the cultural heritage sector (libraries, archives, and academia) as well as in the industry itself. The report addresses the changing technological and organizational circumstances in the creation and collecting of publishers' archives, with an emphasis on the enumeration of the types and variety of digital assets that may form the primary basis for such archives in the future. It emphasizes the extent to which every book published (not just ebooks as such) is in fact "born-digital," and the implications of this shift for future historical and bibliographical scholarship. It concludes with a set of recommendations.