Simon & Schuster will publish the anonymous "O: A Presidential Novel" this month, a political fantasy novel described as "provocative" by its publisher Jonathan Karp on a new website created for the book. The announcement of the book's release has sparked a wave of theories about the identity of its author, with speculation ranging from Joe Klein and humorist Christopher Buckley to Jon Stewart and Obama campaign guru David Plouffe. Even HuffPost's own Howard Fineman.
Here are a roundup of a few key suspects. Who do you think wrote "O"? Let us know in the comments section below.