“Deceptive Practice” is pretty much pure pleasure if you are interested in magic or vaudeville or, perhaps, the psychology of deception. The famous magician, card-shark, and vaudeville archivist/historian Ricky Jay talks to the camera for a 100 minutes, an extended digressive, and ruminative monologue illustrated with footage of astounding “effects” -- the term that Jay uses for magic tricks. (The film is directed by Alan Edelstein and Molly Bernstein.) Jay was born Richard Potash, a Jewish kid from Elizabeth, New Jersey. His grandfather, Max Katz, was a Viennese immigrant, a self-taught accountant, and amateur magician. Katz learned various skills by hiring famous practitioners of the arts to teach him their techniques -- or, at least, those techniques that they were willing to divulge. (As an example, Katz hired a checkers wizard to teach him that game as well as various sleight-of-hand practitioners to tutor him in magic and card tricks) Katz was close to his grandson and passed on his skills to the young boy and, as an adult, Ricky Jay portrays magic and card sleight of hand as disciplines passed on from master to pupil, crafts taught by example and long, arduous discipline, Zen-like study with a “Sensei” to use a term promoted by the film. Jay describes the peculiar sociology of magic in terms of the relationship between teacher and disciple and much of the film is devoted to magicians that Jay regarded as his mentors. These men were elderly when Jay knew them, old vaudevillians, and the film preserves their artistry in the form of archival footage of the old wizards performing their stunts. This also gives Jay (and the film) a chance to highlight the magician's world-famous collection of vintage sideshow posters and memorabilia. Jay's mentors were odd-looking ducks, squint-eyed with thick horn-rimmed goggles, often Jewish or Italian, with heavy ethnic accents and strange boxy suits. One of them had huge ears and was only five feet tall. Another is a hulking fat man, another a sort of bargain-basement Clark Gable with a pencil-thin moustache and a great fan of cards held like a bouquet at his chest. None of them made much money; Jay's grandfather, Stan Katz, prepared tax returns for masters of the trade such as Slydini and the Grest Flosso and he warned Jay to stay away from the business. Jay is generous in his praise for his forebears and describes their work in terms approaching poetry. We see old footage of Jay skewering a watermelon with cards that he hurls like razor blades and there are jaw-dropping images of him boomeranging cards -- that is, throwing them out so that they curve back in mid-air and return to his hand. The card tricks and other stunts that the film documents are, of course, amazing and uncanny. Along the way, we learn about armless wonders and midget magicians and there is an account of a trick that Jay performed on one hot day in Los Angeles that, recalled, twenty years later, still causes the woman who witnessed the stunt -- it was done just for her -- to come close to bursting into tears at the lyrical beauty and sheer improbability of the “effect” -- it involved a big slab of ice. Another informant, a hard-boiled martial arts teacher, recalls a trick that Jay did naked, in the shower at his karate dojo, a bit of magic that leaves the man gaping in astonishment even now. Jay, who is by all accounts a cantankerous and difficult man, seems humble, grateful, and, even, kindly in this film. He embodies the ethic of magic by passing his artistry on to a younger disciple, his partner with whom he has been working for close to thirty years now. Jay has a curious assortment of warts on his noble forehead and is dumpy-looking, with a grating high-pitched voice and Jersey shore accent that is the opposite of the mysterious baritone that most magicians affect, but he has an imposing presence. He has been in many films directed by David Mamet (Mamet appears in this documentary as one of the “talking heads” interviewed) and, on screen, he is never less than fascinating, both compelling and strangely charismatic, the kind of figure that you can’t take your eyes off. This documentary, produced by Public Radio’s Terry Gross, is formless and contains material that is beside the point, although fascinating -- did you know that when a magician dies, the mourners break his magic wand? -- and, except for the amazing tricks, it’s visually uninteresting. But the film is not intended to be cinema, not designed as art, but rather as a portrait of a great performer and it is never less than fascinating.