I'm on Peter Criss...Morbid Manor 2/3. I've just made access to the Library and now possess the key. However, there are only 2 locked doors (that I know of) and the key doesn't work. What am I supposed to once I'm in the Library? Do I leave the Library and go somewhere else...or am I supposedto go the 2nd level of the Library (if so, how do I get up there?) Which door doe the key belong???

There's a book that is specially noticeable somewhere at the library. You gotta press it, and as door will open, behind a wall. Get the key, and open the closest locked door with it, and then you'll reach the second level of the library.