While checking the feeds today I saw a post by @dkmathstats about some free open access statistics books offered by Springer Publishing.
While that's good I would like to point out there is a rather good platform devoted to free textbooks: OpenStax. The official link is https://openstax.org/.
As I wrote in a Steemhunt post about this platform:
OpenStax is a platform that offers free digital (or low cost print version) college-level textbooks. The textbooks are peer reviewed by experts in the textbook's subject and are under a Creative Commons license. Perfect for self-learning or for professors to use in a college course.
