The Sigma Protocol

by Robert Ludlum

First published 2001

In Zurich, American banker Ben Hartman's chance reunion with an old friend turns deadly. Soon he's on the run, targeted by a relentless assassin. In Washington, D.C., Justice Department agent Anna Navarro investigates a string of seemingly unrelated deaths, all linked to a half-century-old CIA file. As Ben and Anna's paths collide, they must uncover the shocking truth behind the codename "Sigma" before it's too late.

Genres: adventure, mystery, thriller, action, espionage

Vibes: fast-paced, suspenseful, thought-provoking

Tropes: enemies-to-lovers, investigation

Setting: Switzerland, Washington D.C., Zurich

535 pages · Hardcover · St. Martin's Press

More by Robert Ludlum

• The Cassandra Compact
• Trevayne
• The Holcroft Covenant
• The Scarlatti Inheritence; The Osterman Weekend; The Matlock Paper; The Gemini Contenders
• The Bourne Identity
• The Road to Gandolfo
• The Chancellor Manuscript
• The Apocalypse Watch

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