Most book titles simply describe the contents of the book they are attached to. Crime and Punishment is about crime and punishment, and Brideshead Revisited is about revisiting Brideshead. But a small number of book titles have a rather odd, separate existence, almost as independent literary artefacts. The stories behind them are quite different from the stories behind the actual books. Winnie-the-Pooh, for example is to do with a swan on a pond at a holiday cottage. The Postman Always Rings Twice is about the travails of a screenwriter. And Catch-22 only got that way after a clash with another author, and via a route that included several other numbers. In Why Not Catch-21?, Gary Dexter looks at 50 iconic books and explores the fascinating stories behind how they got their titles.