MKSAP (not the MKSAP for students question book, which is what I think you guys are thinking of) is a study guide for the Internal Medicine boards. It consists of 10 subject based books (the newest version, MKSAP 15, may have more). I just took a quick look at my MKSAP 14 neurology book, and it is 73 pages long, so I'm assuming someone has a a PDF version of that book. I don't know how you could get the PDF. To purchase the whole MKSAP set, you need to go to the ACP website, but I wouldn't recommend that unless you were an Internal Medicine resident. You could probably borrow a copy from your med school or hospital library.