http://en.wikipedia.org/wiki/William_Shakespeare
See Jonathan Bate's The Genius of Shakespeare ISBN 0195128230 , which does a fairly good job of debunking both the various theories regarding alternate authorship for Shakespeare's work and the various reasons (mostly to do with class) that people have had for concocting them.
My particular take on this (encouraged by an English professor or two) is that it's far more economical to take the authorship question at face value: the manuscripts say they're written by a guy named William Shakespeare, and there's no overwhelming reason to disbelieve them. See DoTheSimplestThingThatCouldPossiblyWork. But it's still fun to bandy about the conspiracy theories. Recently, a professor from Sicily won some attention for claiming that Shakespeare was a Sicilian, pointing to the preponderance of Italian settings in the plays.
Ah, but that raises the question: did Shakespeare know about iocaine powder? Makes you re-think that whole Romeo and Juliet thing, doesn't it?
The best I've heard is that the author of the plays was not WilliamShakespeare, but a completely different individual who happened to have the same name. That's scholarship at its best.
See also Pierre Menard, the man who rewrote Don Quixote word for word: http://en.wikipedia.org/wiki/Pierre_Menard_%28fictional_character%29
"Who is Francis Bacon?"
"A chap who wrote Shakespeare's plays."
"Oh. Awfully decent of him."
"Perhaps he owed Shakespeare some money."
"Yes, there's always that."