"March," Brooks' invention of the Civil War adventures of the absent father from Louisa Alcott's classic "Little Women," was awarded the honor Monday.
No Pulitzer was awarded for drama, the first time since 1997.
• Winners: 2006 Pulitzer Prizes
In her novel, Brooks, an Australian journalist with dual American citizenship, takes the character of March, a Union military chaplain, through the war while his wife and four daughters remain home in Massachusetts.
Brooks, reached in Cambridge, Mass., at the Radcliffe Institute for Advanced Study at Harvard, said she was "in a state of disbelief, really. I just can't believe it. It's like being struck by lightning.
"I have no big plans. I think I might have to make some, and they might have to involve some champagne," said Brooks, whose husband, Tony Horwitz, won a Pulitzer in 1995 for national reporting with The Wall Street Journal.
"American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer" by Kai Bird and Martin J. Sherwin was cited for biography.
"Oppenheimer was well known for black hole theory," said Bird. "He as a subject was a black hole — extremely enigmatic, complicated."
The book about the father of the atomic bomb occupied Sherwin for 25 years. "It was a great project for many of those years and for some of those years, a great burden," he said.
"Marty got biography disease — he ended up with over 50,000 pages of archival research. He was drowning in paper at one point," said Bird. "It was Marty's idea. He signed a contract in 1980, came to me in 2000. I was an unemployed biographer." Bird is the author of "The Color of Truth," a biography about McGeorge Bundy and William Bundy.
Sherwin got interested in Oppenheimer while writing "A World Destroyed," a book about the atomic bomb that came out almost 30 years ago.
The prize for poetry went to Claudia Emerson for "Late Wife," poems based on a series of letters to her ex-husband. Emerson, a professor of English at the University of Mary Washington in Fredericksburg, Va., said she was thrilled and surprised about the award.
"It's about recovery and convalescence," she said. "It means a lot to me, because the book is intensely personal."
David M. Oshinsky, a professor of American history at the University of Texas, Austin, was awarded the history prize for "Polio: An American Story."
"I grew up in fear of this disease. I remember the iron lung and the wheelchairs and not being able to go to swimming pools," the author said in talking about a subject he said always interested him.
The prize for general nonfiction went to Caroline Elkins for "Imperial Reckoning: The Untold Story of Britain's Gulag in Kenya."
Minutes after Elkins, an associate professor of African studies at Harvard University, got word of the Pulitzer from her editor, she was still giddy with excitement.
"I am just wonderful," Elkins told The Associated Press. "You can't imagine."
Elkins said the news took her by surprise and she would go celebrate at a local Harvard Square restaurant, Casablanca, with a group of friends.
Yehudi Wyner, a professor of composition at Brandeis University and a frequent visiting professor at Harvard, took the music prize for "Piano Concerto: 'Chiavi in Mano."' The work premiered Feb. 17, 2005 by the Boston Symphony Orchestra.
The Pulitzer board had listed three finalists for drama: "Red Light Winter," Adam Rapp's play about two good friends and their relationships with a young prostitute they pick up in Amsterdam; "Miss Witherspoon," Christopher Durang's surreal fantasy about a perpetually suicidal woman who keeps coming back from the dead; and "The Intelligent Design of Jenny Chow," Rolin Jones' comedy about a bright yet eccentric young woman who builds a humanlike robot.
Yet Pulitzer administrator Sig Gissler said there was no clear-cut drama winner among the scores of entries.
A posthumous special citation was given to jazz legend Thelonious Monk for "a body of distinguished and innovative musical composition" that greatly influenced the evolution of jazz. Edmund S. Morgan, a retired American history professor at Yale University, was awarded a special citation for his body of work.