I'd always assumed (I think like most people) that Shakespeare was Shakespeare, and I saw no reason to believe that he was anyone other than that guy who was born during April 1564 in Stratford upon Avon, until a couple of colleagues began muttering about Marlowe and various other candidates. Since then, I've read up a little on the issue, and I remain convinced that Shakespeare was Shakespeare. As far as I can see, those who feel that someone else did the writing and our Will was a front for some better-educated nobleman who didn't want to be associated with the grubby business of making plays base their fundamental objections to Will being the author on a mix of snobbery and an inadequacy in themselves rather than in the man from Stratford.
I've just ruled out a major candidate for myself - the 17th Earl of Oxford. Apart from the fact that he died in 1604, before a number of Shakespeare's masterpieces were written, I never knew much about him, but in the course of reading some women writers of the Renaissance, I recently did some background research into his first wife, Anne Cecil. Edward de Vere treated her absolutely monstrously: he was raised as a ward of her family, so knew her from early childhood, they married when she was 15 and they had several children together. Four years after their marriage, she bore her first child, a daughter. De Vere repudiated both his wife and his child, largely because her father (Lord Burghley) refused to pay Oxford's outstanding debts or save his treasonous uncle, Norfolk (who had been plotting against Elizabeth I) from execution.
Oxford circulated rumours that his wife had had an affair while she was pregnant, and rejected her entirely on the birth of their daughter. After five years of letters and petitioning, he took her back. It was widely acknowledged in court circles that Anne had never been unfaithful, but nonetheless, Oxford's treatment caused her considerable humiliation. He was explicit in letters and conversations with cousins that he intended to ruin his wife because of the humiliations he felt that his father in law had heaped on him.
He did take her back five years after the repudiation, they had more children, and she died in 1588 in childbirth.
Apart from the deep implausibility of an active courtier of Elizabeth I having the time to write over 100 sonnets and 40 plays as well as several longer poems, apart from the tricky fact of Oxford's demise occurring before the composition of masterpieces such as Lear, Macbeth, Antony & Cleopatra, The Tempest and A Winter's Tale, apart from the fact that Will Shakespeare was quite educated enough to have written his own material, there is the uncomfortable fact that few supporters of De Vere address, of his thoroughly unpleasant personality and morals. De Vere was a man of his time - dismissive of womenkind in general and his wife in particular, and clearly incapable of imagining let alone writing women such as Rosalind, Beatrice, Portia, Viola. And while he might have as personal characteristics the charm and intelligence of thoroughly unpleasant characters such as Iago and Richard III, Oxford clearly lacked characteristics such as compassion, ambiguity and self-knowledge that produced a Benedick, a Hamlet, a Brutus or Cassius, a Richard II...
Reading Shakespeare, day in, day out, attempting to help children to understand his genius and his talent has only confirmed to me that Will Shakespeare of Stratford upon Avon wrote his own plays and was not an original man, but a man who managed to synthesise and reframe key questions of his own age in a way that continues to intrigue and perplex modern readers and audiences. Recently, I've read Peter Ackroyd's biography, Anthony Nuttall's exploration of his ideas and Jonathan Bates's account of his influences and the more I read by Shakespeare himself and of Shakespeare, the more convinced I am that one quite extraordinary man was responsible for the range of poetry and plays that we have as part of our literary canon today. Instead of wasting time trying to make the scanty facts of the plays and the life fit alternative possible writers, people with doubts should return to the works themselves. Whoever wrote them was a consummate man of the theatre, who knew his audience inside out and understood his own and others' humanity better than virtually every other writer before or since - with maybe the odd honourable exception for Homer, or Chekhov, say.
The honest truth is that it does not matter who wrote Shakespeare's oeuvre - we should simply thank the fates or Fortune's Wheel that they were written and survive to enrich us still.