Thief Side Mission: Writing Wrongs

In order to enter the shop, you have to squeeze through a few crates. Once inside, there's a lot of stuff to grab. Don't miss the cash register as you loot. Just hop over the counter to get it. Afterwards, examine the books on the shelf. Find the hidden switch, and a trap door opens. Hop back over the counter, and head down.

On the table in the back is a manuscript. This is the item that you need. Grab it, and everything else you see, and leave once you see the mission complete prompt.To leave, just go back upstairs, and squeeze past the crates.