18 books in series

Sigma Force

Sigma Force is a 25-book series with 18 released primary works first released in 2004 with contributions by James Rollins and Steve Berry.

Sandstorm
Map of Bones
Cover 6

Kowalski's in Love

Black Order
The Judas Strain
The Last Oracle
The Doomsday Key
Cover 4

The Skeleton Key

The Devil Colony
Tracker
Bloodline
The Eye of God
Cover 4

The Devil's Bones

The 6th Extinction
Cover 1

The Midnight Watch

The Bone Labyrinth
Cover 5

Crash and Burn

The Seventh Plague
Cover 1

Ghost Ship

The Demon Crown
Crucible
The Last Odyssey
Kingdom of Bones
Tides of Fire
Arkangel