Order of Agent 21 Books

The Agent 21 series delivers pulse-pounding YA action-adventure thrills from acclaimed British author Chris Ryan. At the heart of these gripping novels is Zak Darke, a young protagonist who earns the codename "Agent 21" after being recruited by a secretive government organization in the aftermath of his parents' tragic deaths.

Ryan launched this compelling series in 2011 with the debut novel Agent 21, and the series continues to captivate readers today. Here you'll find Chris Ryan's Agent 21 books arranged in their publication sequence, which mirrors the chronological story order: