Johnny Carson dominated late-night television for decades, but closely guarded his privacy. Bill Zehme’s biography, “Carson the Magnificent,” tries to break through.CARSON THE MAGNIFICENT, by Bill Zehme with Mike ThomasMaybe late-night TV shouldn’t be called “late-night TV” anymore, with so many viewers consuming it in clips the morning after, on their phones. Yet the genre’s hallmarks — the avuncular host, the sidekick, the band, the monologue, the desk, the guests — linger. Most were stamped on America’s consciousness by Johnny Carson.A new biography about an old reliable, Bill Zehme’s “Carson the Magnificent” harks back to an era when doom and scroll were biblical nouns and Carson’s “Tonight Show” was a clear punctuation mark to every 24-hour chunk of the workweek — less an exclamation point, maybe, than a drawn-out ellipsis. “They want to lie back and be amused and laugh and have a nice, pleasant and slightly … I hate the word risqué … let’s say adult end to the day,” is how a producer in 1971 described the millions tuning in from home, to Esquire.Carson went off the air in 1992, after three decades on “Tonight,” and left this Earth in 2005. Zehme, a journalist known for his chummy celebrity profiles, struck a book deal almost immediately but struggled to get purchase on his subject— “the ultimate Interior Man,” he despaired to a source, “large and lively only when on camera” — and then was diagnosed with late-stage cancer. He died himself last year at 64, and a former “legman” and friend, Mike Thomas, has finished the project, giving it a doubly valedictory feel.Short but florid, “Carson the Magnificent” is a memorial of the monoculture; a steady parade of mostly men chatting companionably to one another on a padded sectional.Carson was a white whale for Zehme (he’d managed to harpoon Hugh Hefner, Frank Sinatra and the “Tonight” successor Jay Leno, though rather delicately, as if with cocktail toothpicks). After months of faxes and some time backstage inhaling the “cloud of spiced cologne that trails him like an entourage,” Zehme formally met Carson in 2002 and the two men, both said to have unusual professional empathy, had a long lunch at Schatzi on Main, the Santa Monica restaurant owned by Arnold Schwarzenegger. Over the years Zehme amassed piles of Carsonia, like a paisley polyester necktie, and interviewed scores of his intimates, including two of his four wives. (The first was named Joan, though she went by Jody, and the next two Joanne and Joanna. “The man just won’t go for new towels,” Bob Newhart joked.)We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe. More