Harper Lee, who wrote one of America's most beloved literary classics, "To Kill a Mockingbird," and surprised readers 55 years later with the publication of a second book about the same characters, died at the age of 89 on Friday.
"To Kill a Mockingbird" was published in 1960 as the civil rights movement was heating up and its unflinching examination of racial hatred in the U.S. South made it especially poignant. Its theme could be summed up with the advice that Atticus gave Scout: "You never really understand a person until you consider things from his point of view - until you climb into his skin and walk around in it."
A statement from Tonja Carter, Lee's attorney in her hometown of Monroeville, Alabama, said Lee had "passed away early this morning in her sleep" there and that her death was unexpected. She would have a private funeral.
Lee lived an almost reclusive life for decades and it had appeared that her sole literary output would be "To Kill a Mockingbird," especially since she acknowledged she could not top the Pulitzer Prize-winning book. That was what made the July 2015 publication of "Go Set a Watchman" such a surprising and somewhat controversial literary event.
See photos of Lee through the years:
Harper Lee through the years
'To Kill a Mockingbird' author Harper Lee dies at 89
circa 1960: American author Harper Lee smiling. (Photo by Hulton Archive/Getty Images)
Author of To Kill a Mockingbird Harper Lee, in local courthouse while visiting her home town. (Photo by Donald Uhrbrock/The LIFE Images Collection/Getty Images)
Author of To Kill a Mockingbird Harper Lee, while visiting her home town. (Photo by Donald Uhrbrock/The LIFE Images Collection/Getty Images)
Photo of Harper Lee, Pulitzer Prize winner in fiction for her novel 'To kill a Mockingbird.' The award was made on May 1, 1961. (AP Photo)
Harper Lee, 36, who gained fame with her first novel, "To kill a Mockingbird," says she's running just as scared as before her success. Her book, which came out in 1960, has since sold six million copies, won a Pulitzer prize and been made into a film recently nominated for an academy award. Harper Lee poses March 14, 1963. (AP Photo)
Watching the filming of a scene for the 1962 movie "To Kill a Mockingbird" are producer Alan Pakula and author Harper Lee, whose Pulitzer prize winning novel has been adapted for the screen. A south Alabama town that was the inspiration for the setting in Lee's book is finding itself as the backdrop for a real-life legal case involving allegations of racism at school. (AP Photo)
In an August 31, 2001, file image at the Stage Coach Cafe in Stockton, Ala., the author Harper Lee, who wrote 'To Kill a Mockingbird.' A recently-discovered sequel, 'Go Set a Watchman,' is due to be published in July 2015. (Terrence Antonio James/Chicago Tribune/TNS via Getty Images)
LOS ANGELES, CA - MAY 19: Writer Harper Lee attends the reception prior to the Library Foundation of Los Angeles 2005 Awards Dinner honoring Harper Lee at the Richard J. Riordan Central Library on May 19, 2005 in Los Angeles, California. (Photo by Stephen Shugerman/Getty Images)
LOS ANGELES, CA - MAY 19: Writer Harper Lee (R) receives her award at the Library Foundation of Los Angeles 2005 Awards Dinner honoring Harper Lee at the City National Plaza on May 19, 2005 in Los Angeles, California. (Photo by Stephen Shugerman/Getty Images)
Harper Lee (Photo by Lee Celano/WireImage)
Author Harper Lee (center) signs an original edition of 'To Kill a Mockingbird' (Photo by Lee Celano/WireImage)
NEW YORK - MARCH 13: (U.S. TABS AND HOLLYWOOD REPORTER OUT) Playwright Horton Foote and writer Harper Lee listen to actor Dame Edna read a poem as Foote is honored by the Signature Theatre Company on the eve of his 90th birthday at the Ritz Carlton March 13, 2006 in New York City. (Photo by Paul Hawthorne/Getty Images)
WASHINGTON - NOVEMBER 05: U.S. President George W. Bush (L) hangs a Presidential Medal of Freedom on the neck of Harper Lee (C), Pulitzer Prize winner and the author of 'To Kill A Mockingbird,' during a presentation ceremony for the medal's 2007 recipients in the East Room of the White House November 5, 2007 in Washington, DC. The Medal of Freedom is given to those who have made remarkable contributions to the security or national interests of the United States, world peace, culture, or other private or public endeavors. (Photo by Chip Somodevilla/Getty Images)
WASHINGTON - NOVEMBER 05: U.S. President George W. Bush (R) takes Pulitzer Prize winner and 'To Kill A Mockingbird' author Harper Lee by the arm before presenting her with the 2007 Presidential Medal of Freedom in the East Room of the White House November 5, 2007 in Washington, DC. The Medal of Freedom is given to those who have made remarkable contributions to the security or national interests of the United States, world peace, culture, or other private or public endeavors. (Photo by Chip Somodevilla/Getty Images)
WASHINGTON - NOVEMBER 05: Pulitzer Prize winner and 'To Kill A Mockingbird' author Harper Lee smiles before receiving the 2007 Presidential Medal of Freedom in the East Room of the White House November 5, 2007 in Washington, DC. The Medal of Freedom is given to those who have made remarkable contributions to the security or national interests of the United States, world peace, culture, or other private or public endeavors. (Photo by Chip Somodevilla/Getty Images)
Pulitzer Prize-winning Alabama author, Harper Lee, accepts an award, Wednesday, Jan. 10, 2007, at the Davis Theater in Montgomery, Ala., on the occasion of a performance adaptation of her book "To Kill A Mockingbird," by Alabama high school students. (AP Photo/Kevin Glackmeyer)
Harper Lee, the 80-year-old Pulitzer Prize winning author of "To Kill A Mockingbird," shares a laugh with Gov. Bob Riley at the State Board of Education meeting on Thursday, Jan. 11, 2007, in Montgomery, Ala. Lee received a resolution commending her contribution to public education in the state. (AP Photo/Jamie Martin)
** FILE ** Harper Lee, the 80-year-old Pulitzer Prize winning author of "To Kill A Mockingbird," reacts to a vocal performance by Birmingham public school students at the State Board of Education meeting on Thursday, Jan. 11, 2007, in Montgomery, Ala. Lee received a resolution commending her contribution to public education in the state. (AP Photo/Jamie Martin)
FILE - In this Aug. 20, 2007 file photo, "To Kill A Mockingbird" author Harper Lee smiles during a ceremony honoring the four new members of the Alabama Academy of Honor, at the state Capitol in Montgomery, Ala. The ascendance of Tonja Carter, who worked in Lee's older sister Alice Leeâs law office before going to the University of Alabama law school, graduating in 2006 and becoming her partner, brought more aggressive legal tactics on Harper Leeâs behalf. (AP Photo/Rob Carr, File)
Pulitzer Prize-winning Alabama author, Harper Lee, talks to friends backstage, Wednesday, Jan. 10, 2007, at the Davis Theater in Montgomery, Ala., on the occasion of a performance adaptation of her book "To Kill A Mockingbird," by Alabama high school students. (AP Photo/Kevin Glackmeyer)
Copies of Harper Lee's 'Go Set a Watchman' are on display as part of a global release at a bookstore in Seoul on July 14, 2015. Copies of Lee's eagerly awaited, but controversial second novel flew off the shelves more than half a century after the groundbreaking success of 'To Kill a Mockingbird.' AFP PHOTO / JUNG YEON-JE (Photo credit should read JUNG YEON-JE/AFP/Getty Images)
Signs outside the old Monroe County Courthouse refer to "Go Set A Watchman" and Harper Lee on the afternoon of the book's release in the hometown of "To Kill a Mockingbird" author Harper Lee, in Monroeville, Ala., Tuesday, July 14, 2015. (AP Photo/Andrea Mabry)
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In the first book, Atticus Finch was the adored father of the young narrator Scout and a lawyer who nobly but unsuccessfully defended a black man unjustly accused of raping a white woman. But in "Watchman," an older Atticus had racial views that left the grown-up Scout greatly disillusioned.
Lee reportedly had written "Go Set a Watchman" first but, at the suggestion of a wise editor, set it aside to tell a tale of race in the South from the child's point of view in the 1930s.
For many years, Lee, a shy woman with an engaging Southern drawl who never married, lived quietly and privately, always turning down interview requests. She alternated between living in a New York apartment and Monroeville, where she shared a home with her older sister, lawyer Alice Lee.
After suffering a stroke and enduring failing vision and hearing, she spent her final years in an assisted living residence in Monroeville.
"When I saw her just six weeks ago, she was full of life, her mind and mischievous wit as sharp as ever," her agent, Andrew Nurnberg, said in a statement. "She was quoting Thomas More and setting me straight on Tudor history."
The movie version of "To Kill a Mockingbird also became an American classic. It won the Academy Award for best picture in 1963 while Gregory Peck, who played Atticus and would become Lee's good friend, was named best actor.
See more notable people we lost in 2016:
Notable people we lost in 2016 (deaths)
'To Kill a Mockingbird' author Harper Lee dies at 89
January 1 -- Former U.S. Sen. Dale Bumpers, D-Ark., seen here in 2006, passed away at the age of 90. Bumpers' signature moment on the national stage came in 1999, just weeks after leaving the Senate, when he defended Pres. Bill Clinton — who had worked for a challenger's 1974 campaign — before the U.S. Senate during his impeachment trial.
(AP Photo/Danny Johnston)
January 4 -- Robert Stigwood, manager of the Bee Gees and Cream.
(Photo by Michael Putland/Getty Images)
January 4 -- Country singer Craig Strickland was found dead at age 29 from hypothermia.
(Photo via Instagram)
January 6 -- Pat Harrington, Jr., actor in 'One Day at a Time,' died at 86 from complications from Alzheimer's disease.
(Photo by CBS via Getty Images)
January 11 -- Singer David Bowie died after battling cancer for 18 months. He was 69.
(AP Photo/Marty Lederhandler, FIle)
January 14 -- Actor Alan Rickman, popular for playing Professor Snape in the 'Harry Potter' films, died at 69 after battling cancer.
(Photo by Mike Pont/WireImage)
January 18 -- Glenn Frey, founding member of The Eagles, died at age 67 due to complications from multiple ailments.
(Photo by Tommaso Boddi/WireImage)
January 29 -- Paul Kantner, guitarist, vocalist and founding member of the band Jefferson Airplane, passed away at age 74 of multiple organ failure following a heart attack.
(AP Photo/Shawn Baldwin, File)
February 2 -- Jibri Bryan, #34, of the Mercer Bears was killed in a shooting at age 23.
(Photo by Streeter Lecka/Getty Images)
February 4 -- Maurice White, founder of Earth, Wind & Fire, died from the effects of Parkinson's disease at age 74.
(Photo by Richard E. Aaron/Redferns)
February 4 -- Astronaut Edgar D. Mitchell, the sixth person to walk on the moon, passed away at 85 under hospice care.
(Photo via NASA)
February 13 -- United States Supreme Court justice, Antonin Scalia.
(AP Photo/Haraz N. Ghanbari)
February 19 -- Author of the beloved novel To Kill A Mockingbird, Harper Lee.
(AP Photo, File)
March 9 -- Beatles producer Sir George Martin passed away at age 90, as announced by Ringo Starr on Twitter.
(Photo by Vince Bucci/Getty Images)
March 16 -- Singer Frank Sinatra Jr.
(Photo by Express/Express/Getty Images)
March 24 -- Comedian Garry Shandling at age 66.
(AP Photo/Chris Carlson, File)
March 29 -- Oscar winning actress Patty Duke, at the age of 69.
(Photo by ABC Photo Archives/ABC via Getty Images)
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SAD DAY IN MONROEVILLE
Spencer Madrie, owner of the Ol' Curiosities & Book Shoppe dedicated to the work of Lee and other Southern authors, said Monroeville was in a somber mood.
"You wish somebody like that could go on forever and be this lifelong legend," he said. "You don't ever consider somebody like that passing, even though her legacy will last for generations after."
Lee's state of mind would become an issue last year when plans were announced to publish "Go Set a Watchman." Some friends said that after the death of her sister Alice, who handled Harper's affairs, lawyer Carter had manipulated Lee to approve publication.
Carter had said she came across the "Watchman" manuscript while doing legal work for Lee in 2014 and an investigation by Alabama state officials found there was no coercion in getting Lee's permission to publish.
A family friend, the Reverend Thomas Lane Butts, told an Australian interviewer that Lee had said she did not publish again because she did not want to endure the pressure and publicity of another book and because she had said all that she wanted to say.
Lee essentially quit giving interviews in 1964 and rarely made public appearances. She did regularly attend an annual luncheon at the University of Alabama, however, to meet with the winners of a high school essay contest on the subject of her book.
In November 2007, she went to the White House to accept a Presidential Medal of Freedom from President George W. Bush, who at the time called her book "a gift to the entire world."
Bush said in a statement on Friday that he and his wife, Laura Bush, a former librarian, mourned Lee. "Harper Lee was ahead of her time and her masterpiece 'To Kill a Mockingbird' prodded America to catch up with her," he said.
News of Lee's death spread widely on social media and tributes poured in from well-known figures, such as Apple Inc Chief Executive Officer Tim Cook, who quoted the author in a tweet by saying, "Rest in peace, Harper Lee. 'The one thing that doesn't abide by majority rule is a person's conscience.'"
CHANGING RACIAL VIEWS
Nelle Harper Lee was born April 28, 1926, in Monroeville, the youngest of four children of A.C. and Frances Finch Lee and a descendant of Civil War General Robert E. Lee. Like Scout, Lee grew up a tomboy.
Lee had studied law at the University of Alabama but, six months before finishing her studies, she went to New York in the early 1950s to pursue a literary career while working as an airline reservation clerk.
In 1956 friends Michael and Joy Brown gave Lee a special Christmas gift, a year of financial support so she could work full time on "To Kill a Mockingbird."
An estimated 30 million copies of the book were sold. It would become required reading in many American schools but the American Library Association said it was frequently challenged by those who did not like its subject matter.
Lee also played a key role in researching another great American book by Truman Capote, her childhood friend and the inspiration for the frail, precocious Dill in "To Kill a Mockingbird."
In 1959 she accompanied Capote to Holcombe, Kansas, to work on "In Cold Blood," the chilling account of the murders of a farming family. Her mannerly, down-home approach undoubtedly smoothed the way for the flamboyant Capote.
There was speculation that Capote helped her write "To Kill a Mockingbird" but in his 2006 biography, "Mockingbird: A Portrait of Harper Lee," Charles J. Shields disputed that. He also said Lee's contribution to Capote's "In Cold Blood" was greater than believed.
Lee's sister said the authors eventually fell out because Capote was jealous of Lee's Pulitzer, which she won in 1961.
In 2006 Lee wrote a piece for O magazine about developing a childhood love of books, even though they were scarce in Monroeville.
"Now, 75 years later in an abundant society where people have laptops, cell phones, iPods, and minds like empty rooms, I still plod along with books," she wrote.