Sigma Force

Every book in the Sigma Force series in reading order, all 24 of them, with what each one is about.

1. Sandstorm (2005)
2. Black Order (2006)
3. Map of Bones (2006)
4. The Last Oracle (2008)
5. The Doomsday Key (2009)
6. The Devil Colony (2011)
7. The Skeleton Key (2011)
8. Bloodline (2012)
9. The Eye of God (2013)
10. The 6th Extinction (2014)
11. The Devil's Bones (2014)
12. The Bone Labyrinth (2015)
13. Crash and Burn (2016)
14. The Seventh Plague (2016)
15. Ghost Ship (2017)
16. Kowalski's in Love (2017)
17. The Demon Crown (2017)
18. Crucible (2019)
19. The Last Odyssey (2020)
20. Kingdom of Bones (2022)
21. Tides of Fire (2023)
22. Arkangel (2024)
23. The Judas Strain
24. Tracker