The Origin of Evil is a mystery novel by Ellery Queen (pseudonym of American writers Manfred B. Lee and Frederic Dannay), published in 1951.

The latest gift, a dead dog with a mysterious note in a silver casket around its neck, has caused Leander to have a heart attack and die.

Now Roger Priam (and his sultry wife Delia, who attracts Ellery like a carnivorous plant) has started to receive unusual anonymous gifts as well.

Ellery Queen works out the significance of the series of gifts and the link that connects the notes and arranges a dramatic surprise that traps the criminal—although the true criminal is not known until the final moments of the book.

Earlier novels like The Four of Hearts and short stories featuring gossip columnist Paula Paris were connected with the writers' work in Hollywood for Ellery Queen movies some ten years ago and had a light comedic tone.