A second novel from Harper Lee, the writer of “To Kill a Mockingbird,” will be published July 14, the publisher Harper announced Tuesday.

The announcement set off a wave of social media reaction, mostly positive, and the publisher said it was planning a first printing of 2 million copies — an ambitious but probably justified move.

The novel is titled “Go Set a Watchman,” and it was completed in the 1950s and only rediscovered last fall, the publisher said. It’s basically a sequel to “To Kill a Mockingbird” and focuses on Scout as an adult who’s living in New York City and comes back to Alabama to visit her father during the era of the Civil Rights Movement.

The book, which has 304 pages, was actually written before “To Kill a Mockingbird.”

The publisher issued the following statement on behalf of the 88-year-old Lee, who’s in assisted living at a facility in her hometown of Monroeville, Alabama:

“In the mid-1950s, I completed a novel called ‘Go Set a Watchman. It features the character known as Scout as an adult woman, and I thought it a pretty decent effort. My editor, who was taken by the flashbacks to Scout’s childhood, persuaded me to write a novel (what became ‘To Kill a Mockingbird’) from the point of view of the young Scout.

“I was a first-time writer, so I did as I was told. I hadn’t realized it (the original book) had survived, so was surprised and delighted when my dear friend and lawyer Tonja Carter discovered it. 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. I am humbled and amazed that this will now be published after all these years.”

According to publisher Harper, Carter came upon the manuscript at a “secure location where it had been affixed to an original typescript of ‘To Kill a Mockingbird.'”

The publisher said the book will be released as she first wrote it, with no revisions.

Lee won the Pulitzer Prize for “To Kill a Mockingbird,” but never published a second novel. Since the fame surrounding her first book, Lee has been relatively reclusive and refused interviews. The movie version of the book starred Gregory Peck as Atticus Finch, the father of Scout and a prominent but small-town attorney.

It was first printed in 1960, and the movie came out in 1962.

“This is a remarkable literary event,” Harper publisher Jonathan Burnham said in a statement. “The existence of ‘Go Set a Watchman’ was unknown until recently, and its discovery is an extraordinary gift to the many readers and fans of ‘To Kill a Mockingbird.’ Reading in many ways like a sequel to Harper Lee’s classic novel, it is a compelling and ultimately moving narrative about a father and a daughter’s relationship, and the life of a small Alabama town living through the racial tensions of the 1950s.”

The Associated Press contributed to this report.