The "Bard of Avon" is, unquestionably, one of the most popular and influential playwrights of all time. But while his influence on theater and on the English language are obvious, his life is still somewhat obscure. A fair bit of what we "know" about him is actually informed speculation. For example, we know that he was baptized on April 26, 1564 and buried on April 25, 1616, but the actual dates of his birth and death are not specified anywhere and are simply inferred from the known events and other records.
One of the effects of this obscurity (especially as it relates to his education) is that some scholars have inferred that Shakespeare himself would not have had the education and/or skill to write the plays attributed to him, and have devised various theories identifying others as the true originators of "Shakespeare's" plays. The most widely named possibilities are:
However, while each of these men have their champions, the dominant belief among literary scholars is that Shakespeare did indeed write the works attributed to him, in whole or in part (some plays are collaborations, and how much was written by Shakespeare versus his collaborators isn't always clear).
For more detailed information on Shakespeare's life and works, and on the questions over authorship, check the links in the Resources tab.