Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.

Created by Alex Raymond, this futuristic character first appeared in 1934. Who is he?
alex raymond

Of all the actors who played Doctor Who in the TV series of the same name, who appeared in the most episodes?
doctor who

Which American author wrote the book The Catcher In The Rye in 1951 ?

the catcher in the rye