This list was originally a clone of StackOverflow - List of Freely Available Programming Books with contributions from Karan Bhangui and George Stocker.
The list was moved to GitHub by Victor Felder for collaborative updating and maintenance. It has grown to become one of GitHub’s most popular repositories, with 160,000+ stars, 6000+ commits, 1600+ contributors, and 39,000+ forks.
The Free Ebook Foundation now administers the repo, a not-for-profit organization devoted to promoting the creation, distribution, archiving, and sustainability of free ebooks. Donations to the Free Ebook Foundation are tax-deductible in the US.
Source: Index - free-programming-books
This is an amazing list. You’ll find something good for your eReader.