For example, just about every book that's used in education. Especially ones written by professors. They don't "work."
I know this is probably off-topic, but I must ask, as a young student, why do say that?
Is it because they are usually expensive and required to a course (that's taught by the professor who wrote it)? Because they may be hard to follow? Or is there another reason?
Although I'm forced to say that I only had one teacher ask us to buy books/notes wrote by him. I do have one that give us the book (for both courses he taught) for free (it was my physics teacher, he really likes open-source I guess :)). Although the books are written in Portuguese, you can get them here. You can even download the .tex files.
For example Donald Knuth is/was a professor and even though the Art of Computer Programming may be hard to follow (for me anyways, but I'm a moron :) ) they are considered good books. Same thing with SICP, and other books that I'm forgetting right now.
I'm not from a English speaking country, so maybe it's different over here?