Apparently an important library book as been stolen, and the person most likely to know where it might've gone is a fence. Head to 878.44, -31.80, 34.71 and talk to Mariner Whistlethorn. Note: This is under Qeynos Harbor. Best way to get there is to jump into the water behind the city merchants, turn around to face the arch and swim under it. You'll see a hole to your right, which is where you need to go.
It seems this fence doesn't know where the book is, but you are sent to talk with a man named Pumpy. The bartender you need is actually P.T. Irontoe in North Qeynos. He's at 337.28, -19.86, 152.94 .
He now sends you to talk with a lady called Velia. She is in Crow's Resting Place in The Down Below. Leave the pub and head for the sewer entrance almost directly opposite.
The zone-in is found at -143.74, 0.26, -73.37 and it's the statue right in-front of you. So, double-click that to enter Crow's Resting Place.
Once inside, the woman you aer looking for is Velia Truesight. She's just to your left of zone-in, but if you really need the location, she's at -9.82, -0.39, 6.44 . Hail her and she will give you the book, "The House of the Claymore", though you'll learn something very interesting in the process.