Children and adults, muggles and wizards stayed up late Saturday to celebrate the release of Harry Potter and the Cursed Child, an eighth installment of the Harry Potter saga based on a play with the same name. Edgartown Books and Bunch of Grapes hosted book release parties complete with costumes, dramatic readings, Harry Potter birthday cake, and, at midnight, sales of the new book. And Sunday, Harry Potter's birthday, was a day of reading.