The Chronicles of Prydain

1. 

   Book 1

   The Book Of Three

   Lloyd Alexander

2. 

   Book 2

   The Black Cauldron

   Lloyd Alexander

3. 

   Book 3

   The Castle of Llyr

   Lloyd Alexander

4. 

   Book 4

   Taran Wanderer

   Lloyd Alexander

5. 

   Book 5

   The High King

   Lloyd Alexander

6. 

   Book 6

   The Foundling and Other Tales of Prydain

   Lloyd Alexander

Book data and covers from Open Library (openlibrary.org).