What did William Shakespeare look like?

Early last year, doing research for a book, I started to spend more and more of each day thinking about that question. The thing is, it seems like we should know what he looked like – the greatest writer in English – and to many people it probably feels like we do know.

But we don’t know.

Well, OK, we kind of know. There is one (one!) picture that scholars agree portrays Shakespeare, a black-and-white engraving by a man named Martin Droeshout – please get in touch if you know how on earth to pronounce that name – which shows Shakespeare in a big fancy white collar. All modern images of him are variants of this one, in which he looks blandly authorial, gaze disapproving, hairline beating a hurried retreat from his forehead.

The Droeshout portrait is what you might call, if you were conversant with the most recent technical terms of art history, “bad.” (“Droeshout’s artistic abilities are typically regarded as very limited,” offers Wikipedia.) There’s no life in the picture, no glimmer of genius.

But it’s what we have. All that we have for sure, with the exception of a sadly porcine and generic painted bust in a church in Stratford-upon-Avon. Beyond Droeshout, there are only possibilities, guesses, each one more tantalizing than the last. Among these is the Chandos portrait, which shows a dashing, bohemian young fellow with a gold earring – the Shakespeare we want to believe in.

That’s one of the many credible choices. Among the less credible ones is the hilarious “Janssen” portrait, which used to look uncannily like the Droeshout engraving, until it was painstakingly restored, when it was revealed to look nothing like the Droeshout at all.

Of the numerous possible portraits, though, only one really captured me. It’s a mysterious picture, held in a private collection in, of all places, Ottawa. It’s called the Sanders portrait.

The book I was writing when I got so obsessed with these portraits is called The Vanishing Man. It’s a prequel to my long-running (and bestselling! he said proudly) series about an amateur Victorian detective, Charles Lenox, and it is partly about a secret lost portrait of Shakespeare.

Being a prequel, the book features Lenox in his early, scrappy, hungry days in London. I wanted an echo of Shakespeare’s own youthful hunger there; as I say in the book, longstanding tradition has it that the playwright’s first job in London was minding horses outside of a theater, no doubt dying to be inside instead.

The Sanders portrait became my model. In it, the sitter wears a simple shirt and an open collar; its allure lies not in his garments but in his obvious intelligence, wit, curiosity. His smile is in his eyes, caught in an eternal leftward glance. A label on the back says that it was painted in 1603, the year of the first printing of Hamlet, the year of the plague, the year Queen Elizabeth died. Shakespeare would have been 39.

Stare at the picture for hour after hour – I tacked it over my desk – and you’ll see the playwright in it.

But who knows? The beauty of Shakespeare’s work is that he never stays where you left him last, and the same goes for the man. (Did you know that he himself never once spelled his name the way we do?) "The Vanishing Man" features a kidnapping and a murder, but its title is actually a play on Shakespeare’s elusiveness. The harder I looked for him, it seemed, the more adroitly he kept vanishing. That hasn’t convinced me to stop looking.

Charles Finch's latest book, "The Vanishing Man," published Tuesday from St. Martin's Press. It's a prequel to the Charles Lenox Mysteries series. 

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