The revelation that JK Rowling is the author behind the warmly received novel The Cuckoo's Calling has caused quite a stir! But Rowling is far from the first famous author to adopt a pseudonym; indeed, she joins a rich literary tradition of the pen name--illustrious authors like Charles Dickens and Mark Twain have also used noms de guerre. Today we'll explore twentieth-century authors who opted to publish under different names.