6 books in series

The Secrets of the Immortal Nicholas Flamel

The Secrets of the Immortal Nicholas Flamel is a 7-book series with 6 released primary works first released in 2007 with contributions by Michael Scott.

The Alchemyst
The Magician
The Sorceress
The Necromancer
The Warlock
Billy the Kid and the Vampyres of Vegas
The Enchantress