Le Guin strongly influenced the field of speculative fiction. Jo Walton argued that Le Guin was important in both making the genre more open and accepting of new ideas, and in helping genre writers get mainstream success. "A Wizard of Earthsea" introduced the idea of a "wizard school", which would later be made more famous by the "Harry Potter" series of books, and with popularizing the trope of a boy wizard, also present in "Harry Potter".