I can only assume from this you mean physical torture, and with that I can't help you much. However, if you're interested in more psychological torture, then the classic '1984' by George Orwell works well but is a tad depressing. Also, I haven't read it personally, but I have heard that 'American Psycho' contains graphic stuff like that. I could probably help you more with movies than books, such as the Saw series and Hard Candy - they both deal with very graphic torture sequences.