Ranger's Apprentice Collection - 12 Books:

1) The Royal Ranger

2) The Lost Stories 

3) The Emperor of Nihon-Ja 

4) Halt's Peril 

5) The Kings of Clonmel

6) Erak's Ransom

7) The Siege of Macindaw 

8) The Sorcerer in the North

9) Oakleaf Bearers 

10) The Icebound Land

11) The Burning Bridge 

12)The Ruins of Gorlan.