The digital environment has transformed how data on library material use is collected and reported, providing librarians with more information about usage but less clarity about how to interpret it. This article discusses current approaches to reporting and assessing library book use, addresses the question of what qualifies as a worthwhile use of library materials, and presents an analysis of four years of COUNTER 4 BR2 ebook reports at a single research institution to explore the reliability of page view-level usage data for collection assessment. It reveals ways assessment theory and practice fail to capture the value of library materials throughout the research lifecycle, and argues for an inclusive view of collections use.