A magician never reveals his secrets.

Magicians get the deal about secrets the way baseball players know the score on crying, the way members of Fight Club know never to talk about Fight Club.

So I am prepared to have a somewhat fruitless conversation with Ricky Jay, the master sleight-of-hand artist. Jay is a world-famous magician and multitasker: he’s also an actor, writer, historian and consultant. A documentary about him, “Deceptive Practice: The Mysteries and Mentors of Ricky Jay,” premiered last month at the New York Film Festival. When the folks at Encyclopaedia Britannica needed someone to write the entry on “conjuring,” they called Jay.

Jay has been elusive regarding the subject of his upcoming speaking engagement at the Folger Shakespeare Library. The only hint I get as to the night’s theme is “deception,” and it’s this word I have in mind when Jay’s phone call comes in — from a blocked number, of course.

Jay is speaking in conjunction with the Folger’s exhibition “Very Like a Whale,” an historical exploration of misleading appearances and transformations. He is a voracious collector of rare books on magic and loaned about a half-dozen items from his personal collection to the exhibition.

Actor and magician Ricky Jay. (Jamie McCarthy/GETTY IMAGES)

“ ‘Very Like a Whale’ [is about how] things are not what they seem,” said Jay. “[That] certainly lends itself to my field, which is deception. I’m interested in the idea of deceivers influencing or manipulating people to see what they want them to see.”

Deception is a malicious-sounding word, though Jay said deception used in the name of magic is, in fact, honest: “You tell people you’re going to deceive them, and you deceive them.”

There are videos on YouTube of Jay doing exactly that. In one, he walks a small audience through the steps of a seemingly straightforward card trick, telling the room that he’s going to deal from the middle or bottom of the deck so he winds up with all the aces.

You watch it happen, the patterned red backs of the cards sliding silently across the green mat of the table. You watch Jay’s hands — they’re pretty small, he says, not ideal in his profession, but clearly they suffice. You could swear, on your life, on the lives of all your loved ones, that he dealt from the top like an honest man.

Then he flips over his cards. Four aces. Heart, spade, diamond, club, all in a row.

Jay is enamored of deception. He lingers over this favorite word like food that tastes too good to swallow quickly. His primary interest in deception is its use in magic.

“But,” he added. “I also have an enormous interest in the use of deception in crime.”

Conjuring, also called magic, prestidigitation, or sleight of hand, the theatrical representation of the defiance of natural law.

— Encyclopaedia Britannica

This may be a logical progression of Jay’s passion: having learned to defy the laws of nature, one graduates to defying the laws of man — or, in Jay’s case, to studying law-defying men.

Jay has consulted on con films, once inventing a con for David Mamet’s “House of Games.” It was a twist on a real con that Jay wouldn’t share because, contrary to the belief that there’s no honor among thieves, “I knew people who did it and felt very unwilling to expose the methods of con-men friends of mine.”

Some time later, a policeman in Denver sent Jay a newspaper clipping: Someone had been caught pulling Jay’s con. He’d learned it from the movie.

Jay said, “I remember thinking it was probably the only practical thing I’d ever done in my life.”

His soft spot for criminals doesn’t extend to the murder-and-mayhem types, he said. “I’m interested in the idea of people who are able to seduce money from you.”

Lately, Jay suggested, the allure of con men has been diminished “[because of] Bernie Madoff . . . and, of course, what’s happened with our financial institutions, as well. But it used to be something everybody loved, unless they had a personal experience being conned.”

“Magic is a universal art form. Although it may reflect specific features of nationality, ethnicity, or religion, it thrives without regard to them.”

— Encyclopaedia Britannica

One of Jay’s contributions to “Very Like a Whale” is an early modern book about John Selman. Selman had the audacity to pick pockets during Christmas services while the Eucharist was being served — and while King James just happened to be in attendance. Selman was caught and hanged. As Selman stood on the gallows, making his final speech on Earth, another pickpocket in the audience got to work, lightening the purses of a handful of spectators. (He was caught and hanged, too.)

The Folger already had a copy of that book but the one on display is Jay’s, because Jay’s copy just so happens to be signed by William Henry Ireland, one of the greatest forgers of Shakespeare’s signature in history.

“So this master forger signs a book that’s about a thief who got caught,” said Folger Director Michael Witmore. “And the book itself is owned by one of the greatest sleight-of-hand artists ever.” It’s a con inside a con belonging to a con, like Russian nesting dolls of deception.

“Perhaps conjurers have always understood that when viewers are in a state of amazement, their capacity for accurate recall is diminished.”

— from Encyclopaedia Britannica

Jay grew up around magic. His grandfather was a well-known amateur magician whose friends were, according to Jay, “the best sleight-of-hand magicians in the world.” For much of his life, Jay practiced magic at least eight hours a day, toiling over any given trick for years in private before presenting it to the public.

The downside to reaching Jay’s level of hyper-competency is becoming almost impossible to dupe. Call it Magician’s Irony: Once you’ve mastered magic tricks, there’s hardly any magic that can trick you.

“I love being fooled,” said Jay. “It’s a great emotion. . . . It doesn’t happen an enormous amount anymore.”

And when it does, “I don’t have an incredible desire to figure out what happened,” he said. “I think there’s something deflating about knowing the answer.”

He has a consulting company, Deceptive Practices, that specializes in all things sneaky, from poker and crime to “medical quackery.” Its motto is “Arcane Knowledge on a Need to Know Basis.”

“If we’re working with a director on a film and he needs to know how something works in order to shoot it better, we’ll tell him,” said Jay. “But if he’s curious, we won’t.”

Jay said he doesn’t publish any books that explain how magic is done. He won’t reveal his secrets, with one exception.

“If I see someone who seems to be serious and talented,” he said. “Then I’m willing to share.”

Ricky Jay

Nov. 8 at 8 p.m. in the Folger Old Reading Room, www.folger.edu, 202-544-4600.