Diana Wynne Jones books in order
45 books in the catalogue, about 273 hours of reading in all; the shortest takes 35 minutes and the longest 14 hours.
2 series and 42 standalone books in the catalogue.
Dalemark Quartet
4 books 1 
Cart and Cwidder 3.7 h 
The Crown of Dalemark 8.7 h
Cart and Cwidder 3.7 h 2 Drowned Ammet length not known
3 The Spellcoats length not known
4 The Crown of Dalemark 8.7 h Chrestomanci series
7 books Charmed Life length not known
The Magicians of Caprona length not known
Witch Week length not known
The Lives of Christopher Chant length not known
Mixed Magics length not known
Conrad's Fate 6.7 h The Pinhoe Egg length not known
Standalone books
Fire and Hemlock 7.7 h 
The Ogre Downstairs 4.1 h 
Witch's Business 3.4 h 
Dogsbody 4.4 h 
Eight Days of Luke 3.8 h 
Power of Three 5.7 h 
Charmed Life 5.0 h 
The Magicians of Caprona 4.9 h 
The Homeward Bounders 4.1 h 
The Time of the Ghost 4.7 h 
Witch Week 5.0 h 
Archer's Goon 5.9 h 
Warlock at the Wheel 3.1 h 
Howl's Moving Castle 5.6 h 
A Tale of Time City 6.2 h 
The Lives of Christopher Chant 5.8 h 
Castle in the Air 5.5 h 
Black Maria 4.1 h 
Wild Robert 1.8 h 
A Sudden Wild Magic 7.3 h 
Yes Dear 35 min 
Hexwood 7.0 h 
Minor Arcana 5.3 h 
Mystery Stories 4.1 h 
The Tough Guide to Fantasyland 4.3 h 
Deep Secret 7.0 h 
Dark Lord of Derkholm 8.8 h 
Mixed Magics 3.5 h 
The Chrestomanci Quartet 12.2 h 
The Year of the Griffin 5.0 h 
The Chronicles of Chrestomanci, Volume 1 11.2 h 
The Chronicles of Chrestomanci, Volume 2 10.1 h 
The Dalemark Quartet 14.4 h 
The Merlin Conspiracy 8.6 h 
Unexpected Magic 10.6 h 
The Pinhoe Egg 9.2 h 
The Game 3.3 h 
House of Many Ways 6.0 h 
Enchanted Glass 5.9 h 
The Dragon Book 8.2 h 
Stories 7.9 h 
Earwig and the Witch 2.7 h