Go Set a Watchman will be published July 14, and the chance to read a second novel (whether or not it is a second novel) by an 89 year-old author has no shortage of hype. A documentary is scheduled for the week of publication. Bookstores are prepping for midnight release parties. But according to Jeffrey A. Trachtenberg in the Wall Street Journal, it’s To Kill a Mockingbird that’s getting a big bump in the months before Lee’s second book hits shelves.

You’d expect a bump in the backlist for a highly anticipated second novel, but this one is astronomical. Between February 3 and May 30, as readers admitted they’d skimmed their high school copies of the book or decided to revisit an old favorite, HarperCollins reports it shipped 369,000 copies of the hardcover and trade paperback editions.

Not only that, but in the same period of time, 155,000 copies of the ebook sold for HarperCollins. (That ebook is still pretty recent, since Lee was hesitant to part with digital rights. It was published in July 2014.)

That’s not the end of the blockbuster ascent of Lee’s backlist. Another 165,000 copies of the mass market edition were shipped by Grand Central Publishing. The book vaulted to #18 in Amazon’s bestsellers.

And the excitement isn’t just in the U.S. In the UK, Penguin Random House reported that sales of the book are up 153% from last year.

Lee will not be touring for the new book. Alexandra Alter of The New York Times reports that booksellers are “finding creative ways to draw in customers and capitalize on the widespread anticipation, with read-a-thons, midnight openings, film screenings, Southern food and discussion groups.”

Kate Weiss, the head of events for Carmichael’s Bookstore in Louisville, says she may even conduct a conversation on the controversy around this book’s discovery and publication. You can catch up on our coverage of that here.