That ticking noise you hear is the countdown to the release of the new Harper Lee novel, “Go Set a Watchman,” which will be in bookstores next Tuesday.

Readers have been waiting forever for this book — if not since 1960, when Lee published “To Kill a Mockingbird,” then at least since February, when the forthcoming publication of the new book was announced.

Lee wrote “Watchman” in the 1950s, before “Mockingbird.” It features the character known as Scout as an adult returning to her hometown, with flashbacks to her childhood. Lee’s editor liked the flashbacks and urged Lee to focus on those, and “Mockingbird” was born. The book won a Pulitzer Prize and is considered one of the most important novels of the 20th century, while “Watchman” was never published and disappeared from view — until now.

Across the country, bookstores are gearing up for Tuesday’s release, some staying open until midnight (or opening very early on the 14th), some hosting parties with Southern food and music, many showing the 1962 movie starring Gregory Peck as Scout’s father, Atticus Finch. Most Barnes & Nobles across the country — including many in the Twin Cities area — are hosting marathon readings of “To Kill a Mockingbird,” on Monday.

The Wall Street Journal and the Guardian of London newspapers will publish the first chapter of the book online on Friday. The Guardian will also publish the first chapter in its print editions on Saturday.

So far, only one sentence of the book has been released to the press: “Every man’s island, Jean Louise, every man’s watchman, is his conscience.”

Here’s what’s going on in the Twin Cities area:

Magers & Quinn, 3038 Hennepin Av. S., Mpls., will host a marathon reading of “Mockingbird” starting at 10 a.m. Saturday. Anyone who preorders a copy of “Go Set a Watchman” that day will also receive a coupon for $10 off a $30 purchase, good through the end of August.

Barnes & Noble: Many of the Barnes & Noble stores in the Twin Cities area will host marathon readings of “To Kill a Mockingbird” on Monday, including the stores at the Mall of America, Burnsville, Eden Prairie (Eden Prairie’s mayor, Nancy Tyra-Lukens, will take part in the reading), Edina, Maple Grove, Maplewood, Minneapolis’ Calhoun Village, Minneapolis’ Nicollet Mall, Minnetonka, Roseville’s Har Mar Mall and Woodbury.

In most cases, the readings begin at 9 a.m. and customers can volunteer to read.

Barnes & Noble Galleria, though, has invited local authors to read, including Erin Hart, Brian Freeman, Lin Enger, Jon Odell and Carol Connolly. That event begins at 3:30 p.m. Monday.

Barnes & Noble Galleria will also host a weeklong event called Walk a Mile in My Shoes, based on Atticus Finch’s advice to Scout: “You never really know a man until you stand in his shoes and walk around in them.” Members of the public are invited to drop off a pair of shoes along with a story tag — a line or a paragraph that describes the shoe owner’s identity or values. Shoes can be dropped off any time before July 13 and can be picked up again beginning July 18. (Shoes not retrieved by July 25 will be donated to charity.)

SubText Bookstore, 6 W. 5th St., St. Paul, will host poet/baker Danny Klecko, who will lead a discussion of “Watchman” at 7 p.m. July 15.

Moon Palace Books and the Heights Theater, 3951 Central Av. NE., Columbia Heights, will team up for a screening of the movie “To Kill a Mockingbird” at 7:30 p.m. July 20. Admission is $8, and Moon Palace will have copies of both novels on sale in the theater lobby.