Which Harry Potter book was the first to be published simultaneously around the world?

Harry Potter and the Deathly Hallows was the first Harry Potter book published simultaneously around the world.

The seventh and final main novel was released on 21 July 2007 at 00:01 British Summer Time. Publishers coordinated the launch to reduce the chance of unauthorized copies and spoilers appearing before readers could obtain the book. It was issued in the United Kingdom by Bloomsbury and in the United States by Scholastic.

The novel follows Harry, Ron, and Hermione as they search for Horcruxes and confront Lord Voldemort. Its publication ended the main sequence that had begun with Harry Potter and the Philosopher’s Stone in 1997.

Earlier books had already received major international launches, but Deathly Hallows received the especially notable simultaneous release. It is sometimes confused with the first film’s worldwide release or with the later two-part film adaptation, which began in 2010 and concluded in 2011.