Which Harry Potter book was published in Britain on 21 June 2003?

Harry Potter and the Order of the Phoenix was published in Britain on 21 June 2003.

It is the fifth novel in Rowling’s seven-book Harry Potter series. The story follows Harry’s fifth year at Hogwarts, where the wizarding authorities resist acknowledging Voldemort’s return. Dolores Umbridge is installed at the school, and Harry and his classmates form Dumbledore’s Army to practice defensive magic.

The book was highly anticipated and set major first-day sales records. Its publication followed Harry Potter and the Goblet of Fire, which had appeared in 2000. The series became longer and more politically serious as its central conflict developed.

The Order of the Phoenix is also the name of a group of witches and wizards opposing Voldemort. Readers sometimes confuse the book’s number with its film adaptation: the fifth novel became the fifth Harry Potter film, released in 2007.