Where God Went Wrong is the first book in a trilogy by Oolon Colluphid. The other two parts of the trilogy are Some More of God's Greatest Mistakes and Who is this God Person Anyway?. Colluphid's trilogy of "philosophical blockbusters" is considered controversial but is less controversial than The Hitchhiker's Guide to the Galaxy.
It is possible that it is related to Colluphid's other book, Well, That About Wraps It Up For God, based on the theory that the existence of the Babel Fish proves the non-existence of God, as they are both related to the subject of God.