BEVERLY HILLS, Calif. — Conan O’Brien fell under the spell of the historian and biographer Robert A. Caro when he was a student at Harvard in the 1980s. The book that made him a fan was “The Path to Power,” the first installment of the multivolume epic “The Years of Lyndon Johnson.”

Mr. O’Brien devoured the second, third and fourth volumes of the still-growing series, and across his 26 years as a talk-show host, he put in numerous requests to interview the Pulitzer Prize winner. Mr. Caro found time over the years to appear on shows hosted by Jon Stewart and Stephen Colbert, but he always said no to Mr. O’Brien.

On Tuesday, there was a happy resolution.

“I’m anxious,” Mr. O’Brien said as he rode in a black S.U.V. from the Warner Bros. Studio in Burbank, where he tapes his TBS show, to Temple Emanuel in Beverly Hills, where he would interview Mr. Caro. “It’s very unusual to meet somebody whose work you’re so familiar with.”

In an interview with The New York Times last year, Mr. O’Brien said, “The Lyndon Johnson books by Caro, it’s our Harry Potter,” and described in detail his many thwarted attempts to sit down with Mr. Caro. The author finally caved on the occasion of his tour for “Working,” his new, relatively slim book on his writing and research methods.