CHICAGO (CBS) — The sequel to Harper Lee’s Pulitzer Prize-winning novel To Kill A Mockingbird hit store shelves on Tuesday, and while readers might already know the characters in Go Set A Watchman, they certainly aren’t the same as we remember.

The Barnes & Noble store in Oak Brook was one of many to open early Tuesday, so fans could get their copy of the highly-anticipated novel.

Readers might be disappointed by a significant change to the main character, Atticus Finch, but were thrilled to finally hold a copy of a sequel 55 years in the making.

“In the literary world, it’s very exciting,” Barnes & Noble manager Reba Osborne said.

Go Set A Watchman hit bookstores Tuesday morning, with some Harper Lee fans anxiously awaiting a copy.

“I’ve been a Mockingbird fan since I was a little girl, so this is great. I’m excited to read about it,” Kathy Selbach said.

Although set after the events of To Kill A Mockingbird, Lee actually wrote Go Set A Watchman first. Some reviewers have speculated Lee hasn’t revised Watchman since finishing Mockingbird.

Osborne said it’s not often a famous author publishes a follow-up to an American classic.

“That’s what we have. There’s very little to compare it to,” she said.

In Mockingbird, main character Atticus Finch defended an African-American man falsely accused of rape. In Watchman, he’s depicted as a racist and segregationist, breaking the heart of now-grown daughter Scout.

“Clearly, for people who have regarded Atticus as a heroic figure, it’s a lot to take in,” Associated Press National Writer Hillel Italie said.

Many readers said they’re prepared to be disillusioned with the Atticus Finch character, but anxious to read more from Lee, who has published only these two books.

“I read the first chapter in the Wall Street Journal. It’s well written,” Ed Klich said.

The Watchman manuscript was found in Lee’s safe deposit box. Her lawyer has hinted there might be a third book on the way.