In Part of learning of Khan Academy I am taking up time to read more as well is there anyone that would recommend books that correlate with Khan Academy content and lessons here is this place to post.
Two books I currently recommend are the following
Jane Austen Pride and prejudice
W.W Rouse Ball A short Account of the history of mathematics
They are provided on Project Gutenberg
( Please Post Title of Books , Website so it can be googled but no hyperlinks or links)