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

[EX Q]: Who succeeded Henry Cooper as British Heavyweight Boxing Champion?
[EX A]: boxing

[EX Q]: Who achieved fame for his ,'Confessions Of An English Opium Eater'?
[EX A]: confessions of an english opium-eater

[EX Q]: Which series of books, first published in 1922, sees the main character's friends named Ginger, Henry and Douglas who call themselves the Outlaws?
[EX A]:
henry