Isaac Bell vs Sigma Force
Two thriller series side by side, straight from the catalog data: Sigma Force is the longer series (14 books vs 11 books); Isaac Bell is the more recent one, starting in 2007. There's no wrong answer — pick the shape that fits your reading appetite, and Shelfmark will keep your place in either (no account needed).
| Statistic | Isaac Bell | Sigma Force |
|---|---|---|
| Author | Clive Cussler | James Rollins |
| Books | 11 | 14 |
| Published | 2007–2017 | 2004–2019 |
| Books per year | 1.1 | 0.9 |
| Start with | The Chase (2007) | Sandstorm (2004) |
| Reading order | Full Isaac Bell order → | Full Sigma Force order → |
Numbers come from the Shelfmark catalog (Wikidata + Open Library). "Books per year" is catalogued books divided by the publication span — a rough cadence, not a quality score.