Below is a loosely-categorized collection of links to CS textbooks in a variety of areas that are freely available online, usually because they are one of the following:
• An open textbook (such as PLAI, SF, or the HoTT book)
• An older book that is out of print, for which the copyright has returned to the original author(s) (such as TTFP)
• An author’s own preprint or draft of a textbook. This includes cases where the author has made special arrangements with a publisher to host an electronic copy of a published text on their homepage while it remains in print.
Most of these I’ve only used for brief personal reference, and have not read in depth. The exceptions, those books I’ve spent considerable time with and highly recommend, are marked with asterisks.
I also include below a list of papers I consider good stand-alone introductions to certain topics, and a list of links to thorough special topics courses.
If you find one of the links below is broken or has moved, feel free to let me know.
Those with time to spare and looking to have less of it may enjoy browsing the QA call numbers in UPenn’s extensive listing of online books. Most of those listed here were found independently over the years, but I’ve just now (June 2020) learned of this excellent repository of links. I’ll add to the links below as I find promising books.