Sorry if I'm late in replying to your message. So, if you have found the four books, You should put the book away from Left to Right
Power of Authority, Your Pain is My Pleasure, The Painful Pleasure Principle, Giving up for Desire.
If you Can't find the book "Giving up for Desire", You have to go to this door.
(Sorry if the photo is not very clear because I am playing on my other phone, not the phone I am typing on now. And sorry if my English was no good)