Digital book archives
This list includes the more reliable sites for finding older books that have been scanned. You may actually find more than one copy of the same title on these sites, and the quality of the scans varies, so flip through several pages before you download something. If you find a copy that was poorly scanned, keep looking to see if a better scan is available.
What books can I find online for free?
The short answer; anything published prior to 1923. But as with anything determined by government regulation, well, it gets complicated! See this overview for more details.
When it comes to theological and Biblical studies works, that means a gold mine of titles is out there at no cost. But knowing where to search for such works can save you considerable time.
What is not helpful is using a simple Google search. A few simple things can make your search more likely to find good results
1. Know the exact title of what you're looking for, or as close as you possibly can. Older works tend to have longer titles that may be known by shorter phrases that really are not the title. A classic example: Calvin's Institutes is not the real title of his work - it is Institutes of the Christian Religion. When in doubt, you can look in the RTS Library catalog or Worldcat.
2. Remember that works originally written in languages other than English may have copyrighted translations still. In other words, a 400 year old book can still be copyrighted if the English translation was done in 1955.
3. Edition or reprint? With older works, they often called a simple reprinting a new 'edition' even though nothing about the content of that book changed. Current publishing practice is that no book is called a new 'edition' unless the content has changed to some noticeable degree. The safest thing to do if you use an older book is to stick with citing the same copy throughout your paper, using the date given most prominently.
A General Rule of Thumb on Citing
If you are citing a book or journal article that you find online (whether in ATLA or elsewhere) that is scanned and made accessible in the same visual format as it is in print, then you will cite it just as you would if you had it in your hands in print. However, if the original print source has been reformatted in any way (e.g., it has been put into HTML format or ePub), then it must be cited as an electronic source (Turabian, SBL, and other guides will show you how to do that).
Also, if it is material "born" on the web, then there is additional information that must be cited. Sections 6.1.6, 6.3.10, 6.4.12-15 of the SBL Handbook address this detail.
Your research papers for seminary classes will always rely upon a mix of print and digital media, books and journals. Develop good research habits early in your seminary education, and those habits will save you much time in future assignments as well as when you graduate.
There are numerous research helps available, such as Badke's Research Strategies.