Years ago I talked to the local head librarian about donating some programming books and stuff. She had requested that they can't be difficult or hard...

Part of the reason I patronize my library is because to me it is like a mental gymnasium, where all this great equipment there to test my intellectual flexibility and endurance, too tough? I go for easier, but I appreciate the hard stuff because at some point, I, or someone else will find them useful.

Yes, we all NEED access to difficult books (and old books before they refined the such subjects and made them so difficult), don't make our libraries and book shops into mere mental playgrounds.