Agent Sonya

Ursula Kuczynski grows up in a German Jewish family, joins the Communist movement and is recruited into Soviet military intelligence. Under the codename Sonya, she operates in Shanghai, Manchuria, Switzerland and Britain, organising clandestine networks while raising children and maintaining the appearance of ordinary domestic life.

Her most consequential British source is the physicist Klaus Fuchs, whose atomic information she passes to Moscow. Macintyre uses archival material and family history to examine how opposition to Nazism, loyalty to communism and professional espionage became intertwined, and how Sonya survived purges, war and counter-intelligence attention that destroyed many of her colleagues.