In any city, in any country, go to any mental institution or halfway house you can get yourself to. When you reach the front desk, ask politely to visit someone who calls himself "The Holder of the Truth". The worker will nod slightly, then turn back to what he was doing. He will not respond if you ask him again, but do not dare ask him a third time, for if you do he will show his true form to you and rend you into strips of flesh on the spot.
Turn to leave. The door has vanished, but there is a trapdoor in the floor that did not exist before. Open it. Preferably with something long; that gives you a better chance of escape should they be waiting for you on the other side. If they are, run; run as far into the asylum as you can. Find a window and jump out, for all the doors are barred or banished. Once you get out of the window, flee as far as you can, preferably crossing as much water as possible, for while it will not stop them, it will slow them. And you will require each second to make peace with your god.
If they are not waiting, jump through the trapdoor. You will land in a splendid library. People in exquisite and elaborate dress are everywhere, chatting, reading, and relaxing. Do not touch any of them or attempt to choose a book, for that is the trigger, and you do not want to pull it.
Look around- you have all the time you need. Eventually you will find a gray-haired man sitting at a desk, stamping an endless pile of books with an old "returned" stamp. Do not attempt to touch him or the books, for if you do all the pleasant people will reveal what they really look like, and if you are driven mad in an instant by what you see then, consider yourself lucky, for you will not feel the pain as they set upon you in a vehement rage.
Instead, ask the librarian one question, and one question only. "Which one holds His law?"
The librarian will look up. His eyes are a color not native to this Earth or even this galaxy; they are a color so impossible that you may be driven mad simply by their gaze. Steel yourself, and stare directly into his eyes. Do not break eye contact, or he will look back down, not wanting to view the scene as the other patrons set upon you. He will tell you a name. It is a long one, but he will give you a card to help remember it. Before you turn to look for the book, ask if he will check it out in advance. He will nod, and stamp the card.
Do not bother looking for the book. It has already been stolen from the library, and you must find it. Close your eyes and say three words: "Find the thief."
Do not open your eyes for ten seconds, for if the prior adventures have not driven you mad, what you see then will.
After ten seconds have passed, open your eyes. You will be across the street from the asylum, still holding the card.
That card is Object 57 of 538. You have checked out the book; it is now your duty to return it.