Edward Norton’s adaptation (or is that adoption?) of Jonathan Lethem’s Motherless Brooklyn opens Nov. 1, after closing the New York Film Festival on Oct. 11.

The project has been in the works for 20 years, but sadly, the best parts of this 1999 bestseller probably won’t make it into the movie.

The book’s main character, Lionel Essrog, has Tourette’s syndrome. He’s prone to tics, both verbal and behavioral. Even a voiceover can’t do justice to Lethem’s descriptions of what it’s like to have a neurological disorder.

An example: “Tourette’s teaches you what people will ignore and forget, teaches you to see the reality-knitting mechanism people employ to tuck away the intolerable, the incongruous, the disruptive — it teaches you this because you’re the one lobbing the intolerable, incongruous, and disruptive their way.”

That said, the film promises to be visually delicious, thick with atmosphere and acting. Norton, famous for deep, risky roles (Primal Fear, Fight Club, The Score), directed, scripted and stars in the film. He convinced Lethem to let him move the story from the 1990s to the 1950s, and turned a postmodern mystery into noir.

The plot revolves around Essrog’s efforts to find the killer of his friend and mentor Frank Minna (Bruce Willis), a shady Brooklyn operator whose detective agency is a front for various criminal activities. Minna has personally trained his partners, plucking them out of a Brooklyn school for orphans when they were teens.

Minna found Essrog’s behaviorisms useful. “Minna loves my effect on his clients and associates, the way I’d unnerve them, disrupt some schmooze with an utterance, a head jerk…”

Spying on reality through the peephole of his afflicted brain, Essrog has the makings of a true detective. Having figured out what makes himself tick, he can spot the secret lives of others.

As he observes in the book: “Conspiracies are a version of Tourette’s syndrome, the making and tracing of unexpected connections a kind of touchiness, an expression of the yearning to touch the world, kiss it all over with theories, pull it close. Like Tourette’s, all conspiracies are ultimately solipsistic, sufferer or conspirator or theorist overrating his centrality and forever rehearsing a traumatic delight in reaction, attachment and causality, in roads out from the Rome of self.”

Norton also fiddled with characters. Gone is Minna’s wife, Julia, a sad New England girl who found solace in Zen meditation but lost it in Brooklyn. Guess the zendos of the book didn’t have enough noir action. The book hinted at an attraction between Essrog and Julia. In the film, his love interest is Laura Rose (Gugu Mbatha-Raw), an urban activist lawyer who unknowingly holds the key to Minna’s murder.

Gone, also, are the creepy crime family fossils, Matricardi and Rockaforte, enthroned in Matricardi’s mother’s brownstone parlor, “a museum diorama of old Brooklyn…exactly as she kept it.”

Instead, a new character, Moses Randolph (Alec Baldwin), channels the film’s malevolence. A powerful city planner reminiscent of Robert Moses, Randolph’s slum-clearing projects smack of racial discrimination. Bobby Cannavale and Willem Dafoe add their own heavy notes to the plot.

Lethem is the author of 11 novels (The Feral Detective is his latest) and half a dozen short story collections. Motherless Brooklyn won the National Book Critic’s Circle Award in 2000, and was written after Lethem returned to live in Brooklyn. He grew up in Boerum Hill, one of the neighborhoods that star in the book.

Along with Court Street, Cobble Hill, and Carroll Gardens, the area was, Lethem writes, “the only Brooklyn, really — north was Brooklyn Heights, secretly a part of Manhattan, south was the harbor, and the rest, everything east of the Gowanus Canal (the only body of water in the world, Minna would crack each and every time we drove over it, that was 90 percent guns), apart from small outposts of civilization in Park Slope and Windsor Terrace, was an unspeakable barbarian tumult.”

The film’s locations are more Manhattan, from Washington Square Park to Harlem, but that “unspeakable barbarian tumult” still applies.