Found in Caldeum in The Scouring of Caldeum quest (Act II). Talk to Leah in the Hidden Camp, then talk to Asheara in the Caldeum Bazaar. That will trigger the refugee evacuation timed event, but more importantly will allow the southwest door to open into the other area of Caldeum. The journal is found on the Charred Iron Wolf corpse, near the center on the north side of the area. May not spawn every time.
