Biographer Robert Caro will release his next project — on audio only — in May

Robert A. Caro, the author best known for his award-winning multi-volume biography of Lyndon B. Johnson, will release his next project exclusively in an audio format, the Associated Press reports.

“On Power,” the celebrated biographer’s sixth book project, will be published on May 9 by Audible, the Amazon-owned retailer of audiobooks.

“On Power” will feature “personal stories that shaped him as a reporter and informed his understanding of political power,” Audible told the AP.

Power has been an overarching theme in Caro’s work. His first book, “The Power Broker,” was a biography of New York urban planner Robert Moses. It won the Pulitzer Prize for Biography or Autobiography in 1974.

He followed that book up in 1982 with “The Years of Lyndon Johnson: The Path to Power,” the first volume in a planned five-book series about the controversial president.

At the 2016 National Book Awards, Caro was awarded the Medal for Distinguished Contribution to American Letters. The third book in his Johnson series, “Master of the Senate,” won the 2002 National Book Award for nonfiction.

Caro’s most recent installment in the series is the 2012 book “The Years of Lyndon Johnson: The Passage of Power,” which won a Los Angeles Times Book Prize and a National Book Critics Circle Award.

The idea for “On Power” came from Audible senior director Tyler Cabot, who attended a speech Caro gave last year at Harvard University.

“My books are an attempt to examine and explain political power: how it is created, how it works, how it can be used — for good and for ill,” Caro told the AP. “I agreed to do ‘On Power’ because I thought it might add something if I talked, in a more informal manner than in my books, about some moments that helped me personally in that learning process.”

The fifth and final book in Caro’s series on Johnson has no title or publication date yet.