The Drowned Temple is a tome found in Act I of Diablo III. It is found in the Drowned Temple. Retrieving it will add to the Historian of Tristram achievement.
It reads as follows:
The Worldstone has been changed. Our children are born weak and suffer short lives. The demon Nereza promised to restore their power but instead turned them into misshapen creatures and sent them to war against us. We may die, but not before she is sent back to the Burning Hells. -- Alaric