(updated / switched link to source article on stack overflow)
So, I wrote my list of some unique programming texts. But on the more practical side, there’s this:
Best and Free Programming Ebooks.
Free full texts, covering: Bash, C, C++, C#, Common Lisp, Haskell Java, JavaScript, Lua, Objective-C, Perl, PHP, PowerShell, Prolog, Python, Ruby, SQL, x86 assembly, algorithms, version control, and a couple other topics. I’ll still be putting together my own preferred lists, but half of what I’ve got is already on this list.