Conversation so far:
What were some of Agatha Christie's first novels?
The Mysterious Affair.
Was this book successful?
CANNOTANSWER.
What is Poirot?
a former Belgian police officer noted for his twirly large "magnificent moustaches" and egg-shaped head.

Question: Was Poirot a character in one of her books?
Self-contained rewrite: Was Poirot a character in one of Agatha Christie's books?