For scholars of fifteenth, sixteenth, and seventeenth-century English literature, the Database of Early English Playbooks (DEEP) is "[a]n easy-to-use and highly customizable search engine of every playbook produced in England, Scotland, and Ireland from the beginning of printing through 1660." This database was created by Alan B. Farmer, an English professor at The Ohio State University and Zachary Lesser, an English professor at the University of Pennsylvania. The pair created the very first version of this database in 1999 when they were graduate students at Columbia University interested in "the marketing of authorship and theatricality on the title pages of early modern English playbooks." Since then, the pair has collaborated with a number of programmers and designers to create the current version of DEEP. Today, the database includes single-play playbooks as well as collections (books that contain plays). Researchers may want to start by perusing the How to Use DEEP page, which provides a helpful tutorial of the specific search fields that can be used to explore this database. In addition, scholars can download all data contained in DEEP in HTML, XML, or CSV format.