The Howl books are a loose series. Although the wizard Howl, his wife Sophie, and the fire demon Calcifer are the main characters in the first book and appear in all of the other stories, they are not the main characters in the other stories.

The first book reveals that the stories all take place in an alternate dimension from ours, but travel between the dimensions is possible. Howl, whose real name is Howell Jenkins, is from our world and was originally from Wales. When he was in college, he learned how to use magic and inter-dimensional travel to become a wizard and take up residence in another world, eventually becoming one of the royal wizards of Ingary. (The other one is also a man from Wales.) Sophie, who is from Ingary, met him and fell in love with him in the first book, when she was under a magical curse. Sophie came to realize that she also has magical talents, which helped her break both her own curse and a spell on Howl. The two of them later marry and have a son called Morgan. Howl is rather vain and somewhat immature, which contrasts with Sophie’s responsible and practical personality.

They live in a castle with magical connections to different places, including Wales, and the castle also physically moves across the countryside. The castle isn’t as big on the inside as it looks on the outside because it’s only the size of the main house they are using. The castle’s movement and magic are controlled by Calcifer, a friendly but temperamental fire demon.

The series is by Diana Wynne Jones, who also wrote the Chrestomanci series and other fantasy books.

Books in the Series

Howl’s Moving Castle (1986)

Sophie Hatter is cursed by an evil witch to be an old woman and takes a job as housekeeper to the mysterious wizard Howl in his magical moving castle.

Castle in the Air (1990)

A young carpet merchant is sold a magic carpet that allows him to live out his fantasies and to rescue a princess.

House of Many Ways (2008)

Charmain Baker has to look after her uncle’s house while he is ill, but her uncle is a wizard, and this is not an ordinary house.