Devoted fans of two-time Pulitzer Prize biographer Robert Caro will find a lot to dislike about his new book, "Working."

For one thing, they'll be upset that it exists at all.

Caro is about seven years into his fifth and final volume of his masterful biography of Lyndon Baines Johnson. In Caro years, that means he's just getting started. But he's 83 and, as he concedes, he can do the math on the chances of finishing that work.

So taking time to provide this recounting of his five decades of work as a biographer — what he calls "random recollections toward a memoir" — means time away from delivering the coda to his LBJ bio.

Another thing Caro followers may be disappointed in is the book's length. Accustomed to hefting the 1,279-page "The Power Broker" and the 1,191-page "Master of the Senate," the new "Working" will be feather-light in their hands at a mere 207 pages.

Lastly, some Caro loyalists may be disappointed that much of "Working" is familiar. It recycles previously published articles, adapts lectures he's delivered and reprints Q&As done with him. The well-worn stories are all there: the selling of his and Ina's house to finance "The Power Broker," moving to the Texas Hill Country for nearly three years to research LBJ and earn the trust of the locals, writing drafts by hand and then typewriter, blowing deadlines by years.

Robert Caro Photo by Joyce Ravid

But there's also newly written material, and it's priceless. Legendary for his relentless research and bloodhound-like tracking of elusive facts, Caro explains how he does it. He describes, for instance, how he focused his search through the 45 million documents in the LBJ Presidential Library to connect the dots on exactly how Johnson, as a junior congressman, suddenly rose to power in Washington.

One anecdote he relates is perhaps the ultimate tribute to him. While Caro was at work one day at the LBJ library, two women said they wanted to talk to him. They were the sister and a friend of a woman who had had an affair with Johnson. They had read "The Power Broker," one of them said, so "We know you're going to find out about Alice."

Also new are stories about how he interviews key witnesses — the aides, colleagues and family of his subjects — sometimes pressing them and pressing them to the point of annoyance, and other times relying on silence to extract details from them. In one of his interviews with Lady Bird Johnson, the discussion was so sensitive he didn't look up from his notebook because he couldn't look her in the eye.

Caro's enthusiasm and his insights into his craft make "Working" fascinating and inspiring, even for those who've heard it all before. It's a master class in research, reporting and writing.

Although "Working" is chock full of personal stories about working on the Robert Moses and LBJ books, at times it seems Caro can't help himself and he veers into long passages about his subjects rather than himself.

While Caro acknowledges his mortality, he nevertheless optimistically looks ahead. He says that when he's done with LBJ he hopes to write his full-blown memoir; "Working," it seems, is just an appetizer. And he has another biography in his sights, although he won't name his target just yet.

First, though, there's the fifth volume to finish — the fifth of a projected three-volume work. It will include LBJ's Vietnam years, and for Caro, of course, that necessitates a trip to Vietnam. That trip hasn't been taken or scheduled.

"I want to go to the great battlefields of Hue," he told a C-SPAN interviewer in 2017. "I want to go to one of these villages [that were bombed], several I could go. There's a lot of stuff I want to do."

Dennis J. McGrath is an editor at the Star Tribune. • 612-673-4293

Working
By: Robert A. Caro.
Publisher: Alfred A. Knopf, 207 pages, $25.