Harper Lee, author of the Pulitzer Prize-winning novel To Kill a Mockingbird, one of the most significant works in the history of American literature, died Friday at age 89 in her hometown of Monroeville, Alabama.
Lee's attorney, Tonja Carter, said she "passed away early this morning in her sleep" and that the death was unexpected.
Her publisher, HarperCollins, also confirmed her death Friday but did not give any other details.
"The world knows Harper Lee was a brilliant writer, but what many don't know is that she was an extraordinary woman of great joyfulness, humility and kindness," said Michael Morrison, head of Lee's publisher HarperCollins. "She lived her life the way she wanted to — in private, surrounded by books and the people who loved her.''
To Kill a Mockingbird tells the story of idealistic white southern lawyer Atticus Finch, who defends an African-American man unjustly accused of raping a white woman.
FILE - "To Kill a Mockingbird" author Harper Lee received the Presidential Medal of Freedom from President George W. Bush in 2007.
The story is set in the Great Depression of the 1930s and is seen through the eyes of Finch's young daughter, Scout. It is as much a story of growing up as it is a tale of racism and injustice.
It was a remarkable novel for its time, published in 1960 when black Americans were battling for civil rights and confronted by violent mobs, indifferent police, and racist white politicians.
To Kill a Mockingbird won a Pulitzer Prize for literature and was made into a 1962 film starring Gregory Peck, who won an Oscar playing Finch.
The book has sold more than 40 million copies worldwide, HarperCollins says, making it one of the most widely read books since it was published.
In a 1991 Library of Congress survey of books that have affected people's live, To Kill a Mockingbird was ranked second only to the Bible.
A stage version of the book will make its Broadway debut next year.
President and first lady Barack and Michelle Obama said Friday that Lee "changed America for the better" and that her book also changed the way Americans see each other more powerfully than 100 speeches could.
But Lee herself avoided the spotlight. She said she never expected Mockingbird to become a success, and she lived quietly in New York and Monroeville.
Her public appearances were few. But she did go to the White House in 2007 — to accept a Presidential Medal of Freedom from President George W. Bush, who called her book "a gift to the entire world."
FILE - A young girl statue reads "To Kill a Mockingbird" by author Harper Lee, in Monroeville, Ala., July 13, 2015. Lee passed away Friday morning at age 89.
She also regularly attended an annual luncheon at the University of Alabama to meet with the winners of a high school essay contest on the subject of her book, and wrote occasional articles for U.S. magazines.
'Legacy will last'
Spencer Madrie, owner of Monroeville's Ol' Curiosities & Book Shoppe, which is dedicated to the work of Lee and other Southern authors, said the town was in a somber mood as word of Lee's death spread.
"You wish somebody like that could go on forever and be this lifelong legend," Madrie said. "You don't ever consider somebody like that passing, even though her legacy will last for generations after."
A private funeral will be held in a few days, a statement from Lee's family said.
The book world was stunned last year when Lee allowed HarperCollins to publish her only other known novel, Go Set A Watchman, which was a prequel to Mockingbird.
The publisher says it was the fastest-selling book in its history, selling more than 1.1 million copies in North America in its first week.