5 books in series

MagicQuest

MagicQuest is a 5-book series with 5 released primary works first released in 1962 with contributions by Nicholas Stuart Gray, Tanith Lee, Elizabeth Marie Pope, Peter Dickinson, and Diana Wynne Jones.

The Dragon Hoard
Tulku
The Perilous Gard
The Seventh Swan
The Magicians of Caprona