The digital artifact known as Early English Books Online (EEBO) is a resource for research on British history and literature between 1473 and 1700. EEBO is a collection of 146,000 mostly English works accessible via an online database, available by subscription from ProQuest. In this article I first review the history of EEBO, which began with cataloging efforts more than a century ago, through the processes that developed the online version used by so many scholars today. I then critically review its limitations, and discuss some of the challenges and drawbacks inherent in the transformation of analog source materials into digital form, including information distortion and loss, format obsolescence, and the challenges of digital preservation.