Double Agents

Aldrich Ames destroyed the CIA’s Soviet spy network for $4.6 million and a Jaguar. Robert Hanssen passed nuclear war plans to Moscow for 22 years. Neither was ever polygraphed. Both sat in the same buildings as the people hunting them.

Double Agents is a global history of betrayal in espionage — why it happens, how it goes undetected for years or decades, and how counterintelligence services eventually find the enemy inside their own ranks.

Drawing on more than fifty cases across three millennia — from Ephialtes at Thermopylae to Ana Montes at the Defence Intelligence Agency — this is not another Cold War spy book. It is an analytical history that asks the questions popular accounts rarely do: not just who betrayed, but why institutions consistently fail to see it coming.

The cases span the world and the centuries. The Cambridge Five, whose penetration of British intelligence lasted decades because no one could believe that men of their class would work for Moscow. Cuba’s DGI, which achieved something no other service managed — complete, systematic penetration of CIA operations over four decades. Kautilya, who wrote the world’s first manual on double agents in 300 BCE. And the two women — Vertefeuille and Grimes — who caught Ames using a spreadsheet, after years of being ignored by the institution they were trying to protect.

The central argument of Double Agents is uncomfortable: the traitor is always a symptom. The institution is always part of the disease.

Global in scope. Rigorous in analysis. Genuinely surprising on every page.

Part of the Espionage Series — a multi-volume history of intelligence from antiquity to the digital age.