Daniel Menaker loves words, and you can see it in every clause, in the rhythms of his language, even in the length of the sentences in his bracing memoir, “My Mistake.” A veteran editor at The New Yorker and Random House, an insider who has always felt like an outsider, he was jolted by lung cancer several years ago into re-­examining his past. He grabs the reader with urgency as he grapples with big questions: What shaped me? Where did I go right and wrong? What has my life meant? His clever, fast-paced prose makes you stop and think and wonder, meandering down your own byways, contemplating the ways his story ­reverberates.

Menaker’s memoir braids together three narratives: family history, literary life, cancer. A red-diaper baby in Greenwich Village in the 1940s, he was the son of loving but irresponsible parents. His mother, a pioneering copy editor at Fortune, had affairs, and his father, a furniture designer and salesman, liked his alcohol. They often left him in the care of a beloved Southern black nanny or a lefty uncle who ran a Jewish guest camp (charades, folk dances) in the Berkshires. Menaker was a smart-aleck kid, as ruthlessly competitive as he was insecure. He studied philosophy and poetry at Swarthmore, picked up an M.A. in English at Johns Hopkins, taught private school in Manhattan but felt lost.

The mistake that haunted his life, and that gives the book its title, occurred over Thanksgiving in 1967. During a family touch football game, Menaker goaded his older brother, Mike, who had bad knees, into playing the backfield on defense. Mike, a lawyer who was newly married, tried to block a pass and tore a ligament. This should have been the kind of sibling-rival spat they joked about years later. Instead, after surgery to repair his knee, Mike developed septicemia and died. Menaker still cannot forgive himself. He would later suffer from panic attacks.