Major characters from the Harry Potter book series include protagonist Harry Potter and Harry's closest school friends, Ron Weasley and Hermione Granger. Other important characters are Albus Dumbledore, the headmaster of Harry's school, and Harry's least-favorite teacher, Severus Snape. The series' villain is the evil wizard Lord Voldemort. The Harry Potter series was written by J.K. Rowling and consists of seven books.
The Harry Potter books span Harry's seven years at the Hogwarts School of Witchcraft and Wizardry, and many characters appear in all seven books, although their relationships with Harry change as they all grow older. For example, Ron Weasley's little sister Ginny begins as a peripheral character but becomes Harry's love interest by the end of the series.
Warner Brothers adapted the Harry Potter series into eight movies, which were released from 2001 to 2011. The movies feature many of the same characters as the books and star Daniel Radcliffe as Harry Potter, Emma Watson as Hermione Granger and Rupert Grint as Ron Weasley.
As of 2015, Warner Brothers is working on two companion movies also set in the Harry Potter world, "Fantastic Beasts and Where to Find Them" and "Fantastic Beasts and Where to Find Them 2," to be released in 2016 and 2018.