Bloodline (Sigma Force)
The Doomsday Key: A Sigma Force Novel
The Last Oracle (Sigma Force)
The Eye of God (Sigma Force)
The Judas Strain: A Sigma Force Novel
Black Order (Sigma Force)
Map of Bones (Sigma Force)
The 6th Extinction: A Sigma Force Novel (Sigma Force Novels)
Sandstorm (Sigma Force)
The Bone Labyrinth: A Sigma Force Novel (Sigma Force Novels)