Harper Lee, author of the American classic “To Kill a Mockingbird,” has announced the publication of her second novel, “Go Set a Watchman,” this summer.

In an announcement from her publisher Harper Collins, Lee says the sequel was written in the mid-’50s but put aside after “Mockingbird” was published in 1960. Lee said she had forgotten about the story, but Tonja Carter, Lee’s friend and lawyer, discovered the long-lost manuscript.

"After much thought and hesitation, I shared it with a handful of people I trust and was pleased to hear that they considered it worthy of publication,” said the 88-year-old Pulitzer Prize winner.

The book is set 20 years after “To Kill a Mockingbird,” with an adult Scout visiting her father Atticus Finch in Maycomb, Alabama.