Day has written and edited four books. His first book, The Modern Invention of Information: Discourse, History, and Power was published in 2001 by the Southern Illinois University Press is an attempt "to understand the interlinking of a variety of historical streams into a discourse on "information".' This is done from the perspective of literary and critical theory, with the objective of understanding how the concept of 'information' is embedded in modern culture."[5] Day does this through the story of Suzanne Briet, the French librarian, author, historian, poet, and author of Qu'est-ce que la documentation? (What is Documentation?), where she viewed "documentation as a movement towards the coordination of organizational activity through standardization."[6] Much of the work for this book went towards an eventual English translation of Briet's book with two other editors in 2006.
Day's next book was an edited collection with Claire R. McInerney entitled Rethinking Knowledge Management: From Knowledge Objects to Knowledge Processes which looked at fundamental issues in knowledge management and knowledge processes. Specifically, the essays covered insights into knowledge management in organizations and societies that went beyond traditional information acquisition and processing by privileging the creative potential of human expression, communication, and meaningful personal and social existence.[7]
In 2014 Day published Indexing it All: The Subject in the Age of Documentation, Information, and Data through MIT Press where he "examines information 'as a cultural and social phenomenon” during the twentieth and twenty-first centuries.'"[8] Again, he relies on his knowledge of Briet to explore indexing and "the transition of indexes from explicit professional structures that mediate the relation of user needs and documentary information seeking, searching, and retrieving to being implicit infrastructural devices in everyday information and communication acts."[9] It was winner of the Best Information Science Book Award from the Association for Information Science and Technology in 2015.
In this respect, this book is not unlike an earlier work by Geoffrey C. Bowker and Susan Leigh Star entitled Sorting Things Out: Classification and its Consequences where the traditional Aristotelian manner of classification breaks down in social contexts.[10]
In addition to these four books, Day has published nearly forty articles relating to the field of Library and Information Science.