Schaff Herzog Encyclopedia of Religious Knowledge
Edited by Philip Schaff (1819-1893) in its English language version, it was based on the third edition of the Realencyklopädie für protestantische Theologie und Kirche founded by Johann Jakob Herzog (1805-1882), and edited by Albert Hauck.
As of 2004, it is in the public domain. The Christian Classics Ethereal Library has scanned a printed copy, and is in the process of correcting and marking-up the entire work.
- New Schaff-Herzog Encyclopedia of Religious Knowledge by Philip Schaff Table of Contents at CCEL