Gottlieb died Wednesday of natural causes at a New York hospital, Knopf Doubleday Publishing Group announced. Caro, who had worked for decades with Gottlieb on his Lyndon Johnson biographies and was featured with him last year in the documentary “Turn Every Page,” said in a statement that he had never worked with an editor so attuned to the writing process.

“From the day 52 years ago that we first looked at my pages together, Bob understood what I was trying to do and made it possible for me to take the time, and do the work, I needed to do,” Caro said in a statement. “People talk to me about some of the triumphant moments Bob and I shared, but today I remember other moments, tough ones, and I remember how Bob was always, always, for half a century, there for me. He was a great friend, and today I mourn my friend with all my heart.”

Tall and assured, with wavy dark hair and dark-rimmed glasses, Gottlieb had one of the greatest runs of any editor after World War II and helped shape the modern publishing canon. His credits included fiction by future Nobel laureates Morrison,Doris Lessing and V.S. Naipaul; spy novels by John le Carré, essays by Nora Ephron, science thrillers by Michael Crichton and Caro’s nonfiction epics. He also edited memoirs by Katharine Hepburn, Lauren Bacall and Washington Post publisher Katharine Graham, whose “Personal History” won a Pulitzer. Gottlieb so impressed Bill Clinton that the former president signed with Alfred A. Knopf in part for the chance to work with Gottlieb on his memoir “My Life.”

Uniquely well-read and unstuffy, he was the rare soul who would claim to have finished “War and Peace” in a single weekend (some reports narrowed it to a single day) and also collected plastic handbags that filled shelves above his bed. Gottlieb was as open to “Miss Piggy’s Guide to Life” as he was to the works of Chaim Potok. On his desk for decades was a bronze paperweight, given to him when he started in publishing, etched with the words “GIVE THE READER A BREAK.”

Gottlieb’s reputation was made during his time as editor-in-chief of Simon & Schuster and later Alfred A. Knopf, where in recent years he worked as an editor-at-large. But he also edited The New Yorker for five years before departing over “conceptual differences” with publisher S.I. Newhouse and was himself an accomplished prose stylist. He wrote dance criticism for The New York Observer and book reviews for The New York Times. He wrote a short biography of George Balanchine, co-authored “A Certain Style: The Art of the Plastic Handbag, 1949-59,” and edited well-regarded anthologies of jazz criticism and 20th century song lyrics. His memoir, “Avid Reader,” came out in 2016.

He was married twice, the second time to actor Maria Tucci, and had three children. He was otherwise so absorbed in work — he was looking over early proofs of a Cynthia Ozick book while counting contractions for his pregnant wife — that the author Thomas Mallon summed up his life as a “busman’s holiday without any brakes.”

In “Turn Every Page,” a joint biography of Caro and Gottlieb directed by the editor’s daughter, Lizzie Gottlieb, Robert Gottlieb referred to editing as “a service job.” He would remind himself that the books he pored over were not his own, while also maintaining the ideal editor-writer relationship was “an equivalence of strength,” in which each shared the best of their talents.

“I am not egoless,” he acknowledged to his daughter.

Caro is still writing his fifth and presumed final volume of the Johnson biographies, a series begun nearly 50 years ago. A Knopf Doubleday spokesperson would not comment on who might serve as its editor.

Born and raised in Manhattan, Gottlieb would say he was born with “extra drive.” He was a lifelong bookworm who recalled taking out up to four novels a day from his local public library. As a teenager, he would visit the library at Columbia University, looking up old copies of Publishers Weekly and studying the bestseller lists.

He eventually attended Columbia, from which he graduated in 1952. After studying two years in England, at Cambridge University, and working briefly in theater, Gottlieb joined Simon & Schuster in 1955 as an editorial assistant, an upstart claiming he took the job to support his wife and child but also so confident that — even then — he regarded himself as “a better reader than anybody else,” he recalled in the documentary.

In the memoir “Another Life,” fellow Simon & Schuster editor Michael Korda would describe the young Gottlieb as resembling “one of those penniless perpetual students in Russian novels,” his glasses so smeared that Korda was amazed he could see. Through the unwiped lenses, Korda noticed eyes that “were shrewd and intense, but with a certain kindly humorous sparkle.”

Within two years, he had taken on a former World War II pilot named Joseph Heller and his partially written novel about the war titled “Catch-18.” As Heller later recalled, he wanted an open mind to handle his shocking satire and had been told by his agent that Gottlieb was known for being “receptive to innovation.” Gottlieb convinced skeptical executives at Simon & Schuster to give the novel a chance.

“The funny parts are wildly funny, the serious parts are excellent,” he told the editorial board.

Gottlieb paid $1,500 for the novel, $750 upon signing Heller, $750 after publication. He also made some “broad suggestions,” including changing the title to “Catch-22,” to avoid confusion with Leon Uris’ “Mila 18.” Released in 1961 to an initially mild response, the book caught on after another Gottlieb author, humorist S.J. Perelman, recommended it to a New York Herald Tribune critic. “Catch-22” eventually became a blockbuster and counterculture touchstone, and Gottlieb became a literary celebrity “most closely associated” with Heller’s novel “among the kind of people who think about such things,” Gottlieb wrote in his memoir.

“But in the years that followed its publication, I more or less put it out of my mind,” he added. “I certainly never re-read it. I was afraid I wouldn’t love it as much as I once had.”

Success only accelerated his drive. He signed up such rising authors as Edna O’Brien,Mordecai Richler and Len Deighton and was hip enough to acquire John Lennon’s collection of verse, vignettes and drawings, “In His Own Write.” He later worked with Bob Dylan on a book of his lyrics and was amazed to find that “this genius rebel and superstar was almost childlike — you felt he barely knew how to tie his shoes, let alone write a check.”

Gottlieb had some letdowns, rejecting Larry McMurtry’s “Lonesome Dove” and struggling with John Kennedy Toole’s “A Confederacy of Dunces.” Toole submitted the novel in the early 1960s to a positive response from Gottlieb, who also suggested numerous revisions. For two years, Toole kept making changes and Gottlieb kept asking for more, telling the author that “there must be a point to everything in the book, a real point, not just amusingness that’s forced to figure itself out.”

Gottlieb finally gave up, and Toole eventually killed himself, in 1969. A decade later, his mother helped get “Confederacy” published by Louisiana State University to public acclaim, the Pulitzer Prize and lasting affection, the kind of fate Gottlieb’s other authors often enjoyed.

Gottlieb’s other successes — he had so many — included Charles Portis’ “True Grit,” Potok’s “The Chosen” and a Pulitzer Prize-winning anthology of John Cheever’s short stories, compiled by Gottlieb over the author’s misgivings. At The New Yorker, which he edited from 1987-1992, Gottlieb published short fiction by Denis Johnson that later became the acclaimed “Jesus’ Son.”

He was otherwise known for introducing a more informal style to the venerable magazine — including a willingness to let the occasional four-letter word appear in print.

An acknowledged workaholic, Gottlieb was also the most personal of editors. When Ephron’s marriage to Carl Bernstein broke up, she and her children stayed for a few months with Gottlieb. He not only called male writers “dear boy,” but eyed every line of such marathons as “The Power Broker,” for which Gottlieb and Caro spent several contentious weeks — side by side — cutting some 300,000 words from a manuscript that originally topped 1 million and still ended up at more than 1,200 pages. They might argue fiercely over the usage of semicolons (Caro favored them; Gottlieb did not) but agreed on Caro’s ambition to write a definitive account of the imperious municipal builder Robert Moses.

“You don’t take on books with which you do not have a sympathy,” Gottlieb told The Guardian in 2016. “Only trouble can arise if instead of wanting to make a book that you like even better than it is, you want to change it into something that it isn’t.”

Gottlieb was equally exacting after signing up a young medical student named Michael Crichton and his novel, “The Andromeda Strain.” He loved Crichton’s story of a deadly virus, but wanted more plot and factual details and less character development.

“He would call me up and say, ‘Dear boy! I have read your manuscript, and here is what you have to do,’” Crichton told The Paris Review in 1994. “And he was not above saying, ‘I don’t know if you can do it this way, I don’t know if you’re up to it, which of course would drive me into a fury of effort.’ It was very effective.”