The other feng shui concern with books in the bedroom are the possibly sharp energy - Sha Chi - pointing at you when you sleep. This energy can be created by hardcover books arranged in a way that sends the so-called poison arrows at you. Thus, it is generally recommended in feng shui to have books in closed bookshelves.
Feng Shui-wise, it is also important to note the energy messages you receive from the books in your bedroom. Are the titles that you look at before you go to sleep and when you wake up in the morning sending you good feng shui energy? Are you waking up with a title such as "Love My Life" or is it "To Die Broke" ?
As everything around you carries a certain quality of feng shui energy, every item in your bedroom subconsciously influences you when you are most vulnerable - during sleep.
Thus, with books, as well as with every other item you bring into your bedroom, there is a potential for either good or bad feng shui energy. It is up to you to decide which energy you want to have close to you.