The 12th and so far final installment of The Merlin Saga, an encyclopedia called Merlin: The Book of Magic, was published in 2011.
The Merlin Saga tells the story of how the eponymous wizard learned how to use magic in his younger years and became the powerful man who would one day mentor King Arthur.
The series was initially comprised of five books, which were collectively titled The Lost Years of Merlin.
T.A. Barron then published The Great Tree of Avalon trilogy, and then wrote the Merlin’s Dragon trilogy, which takes place in between the preceding two series.