Josh Christie, co-owner of Print: A Bookstore in Portland, Me., has signed many a document before a book’s release. But few have come with as many Gilead-like stipulations as the affidavit for the sequel to “The Handmaid’s Tale.”

Mr. Christie committed not only to keeping “The Testaments” in a monitored and locked location, but also to prohibiting any member of his staff to photograph the book or read a single passage before the release date: Sept. 10 at 12:01 a.m.

And yet on Tuesday, a full week before the highly anticipated release, some Amazon buyers had already received copies of the book, social media postings show. That development has i nfuriated independent bookse llers, aggravating long-simmering resentments of Amazon for undercutting their ability to turn a profit.

“Hey, at least we get a dozen cheap enamel pins for running our preorder campaigns and sticking to on-sale dates,” Mr. Christie wrote on Twitter.