In the Reviews section of the monastery, I found a review for Practical PostgreSQL however, the review wasn't very favourable. But in one of the replies another book was mentioned in a more favourable light: PostgreSQL Developer's Handbook. Maybe you should check out this one.
Aside: there are some really useful Book Reviews in the monastery, after buying a couple of donkeys in the past, I always make sure to check out the verdict here before I even consider handing over my hard earned cash!

Martymart