'Go Set a Watchman' Shows Literary Hero Atticus Finch’s Dark Side

— -- In the classic book and iconic film “To Kill a Mockingbird,” Atticus Finch stood as a towering symbol of morality, courage and wisdom.

But a new book by author Harper Lee now casts him in a different light. It shows that the lawyer who took on racism and injustice is no saint. In the book “Go Set a Watchman,” to be released Tuesday, readers meet a different, older and racist Finch.

Daniel D’Addario, Time magazine’s culture reporter, remarked on the significance of the book.

"I think it's undeniable that this is the literary event of the decade, if not more … we had absolutely no reason to expect this was ever coming,” D'Addario told ABC News. "For decades we've only ever seen Atticus one way, as an unambiguous hero with nothing but the best of motivations, but even our heroes can have extremely complicated mindsets."

In “Go Set a Watchman,” which takes place 20 years after “Mockingbird,” Finch has reportedly attended a Ku Klux Klan meeting and questions the benefits of desegregation.

Lee actually wrote “Go Set a Watchman” before "To Kill a Mockingbird," but the book remained unpublished for more than 50 years.

“Go Set a Watchman” is already a hit, smashing pre-sale records at libraries and stores, including online retailer Amazon. Academy Award-winning actress Reese Witherspoon lent her voice to the audio book.

“Good Morning America” obtained an exclusive photo of Lee, 89, receiving a first published copy of the book.

The photo was taken at an "intimate luncheon" in Monroeville, Alabama, June 30, where HarperCollins president and publisher Michael Morrison and Harper publisher Jonathan Burnham presented Harper Lee with the first copy of her book off the presses, a HarperCollins official told ABC News.

Fans of Lee's first book are already sounding off on social media.

One poster wrote, “Any book where Atticus Finch is a bad guy is not a book I want to read.”

Another chimed in, “Atticus Finch is revealed as a racist in new book. Hero no more.”

The book's publisher, HarperCollins, has said Lee requested "Go Set a Watchman" be published as written, with no editorial intervention.

"As her publishers, we naturally respected her wishes," HarperCollins told ABC News in a statement.

"The question of Atticus's racism is one of the most important and critical elements in this novel, and it should be considered in the context of the book's broader moral themes," the statement continued. "'Go Set a Watchman' explores racism and changing attitudes in the South during the 1950s in a bold and unflinching way. At its heart, it is the coming-of-age story of a young woman who struggles to reconcile the saintly figure of her beloved father with her own more enlightened views. In Go Set a Watchman, Scout takes center stage as we witness her anger toward and stand against prejudice and social injustice. By confronting these challenging and complex issues at the height of the Civil Rights movement, the young Harper Lee demonstrated an honesty and bravery that makes this work both a powerful document of its time and a compelling piece of literature."

The book will be available for downloads Tuesday , the same day it goes on sale in stores.