The Post-Reformation Digital Library (PRDL) is a select database that organizes the vast array of publicly available digital sources on the development of theology and philosophy during the early modern era (late 15th-18th c.)
The Internet Archive offers over 20,000,000 freely downloadable books and texts. There is also a collection of 2.3 million modern eBooks that may be borrowed by anyone with a free archive.org account.
The Aquinas Translation Project is a web-based project which seeks to provide scholars, religious and any interested individuals with translations of St. Thomas Aquinas's works not readily available in English
The Clifford E. Barbour Library at PTS houses a collection of more than 400,000 cataloged items, mainly in Protestant theology and Biblical studies. Specialized holdings include works in the Presbyterian and Reformed tradition, particularly in the areas of theology, church history, missions, ecumenics, and hymnology. The library also houses the Seminary Archives.
The Christian Classics Ethereal Library is a digital library of hundreds of classic Christian books selected for edification and education. The online www.ccel.org server reaches several million different users each year.
Project Gutenberg was the first provider of free electronic books, or eBooks. Michael Hart, founder of Project Gutenberg, invented eBooks in 1971 and his memory continues to inspire the creation of eBooks and related content today.