Iron Wolf Captain's Journal is a tome found in Act II of Diablo III. It is found on a corpse of Iron Wolf Captain, which can be randomly found in any desert area between Caldeum and Alcarnus during and after the City of Blood quest.
It is required for the Judge of Character achievement.
It reads as follows:
Another sunset, and Alcarnus is still safe from the sudden madness that plagues Caldeum. Though we are seeing an influx of hooded pilgrims for some Zakarum holy day, the... demons out there are keeping their distance. I will double the guard at the gate. We must not be unprepared if our luck turns. — Iron Wolf Captain