The Ravings of a Deranged Mind is a tome found in Act V of Diablo III. It is found in the House of Madness, located in Westmarch Heights. After the madman Hamish's defeat, the journal drops. Obtaining the journal will add to the People Finder achievement.
It reads as follows:
I can hear them. The voices speak to me again! What? Death is coming? But I can't die! I can't! I am too important to have my life just thrown away. Please, tell me how I can avoid my fate. You want me to do what? Must I? Oh yes, yes, I will! I swear it. I will do anything.