In the quiet Cotswolds village of Great Rollright in 1945, an elegant housewife emerged from her cottage to go on her usual bike ride. A devoted wife and mother-of-three, Mrs Burton seemed to epitomise rural British domesticity.

However, rather than pedalling towards the shops with her ration book, she was racing through the Oxfordshire countryside to gather scientific intelligence from one of the country's most brilliant nuclear physicists. Secrets that she would transmit to Soviet intelligence headquarters via the radio transmitter she was hiding in her outdoor privy.

Far from a British housewife, Mrs Burton - born Ursula Kuczynski, and codenamed 'Sonya' - was a German Jew, a dedicated communist, a colonel in Russia's Red Army, and a highly-trained spy. From planning an assassination attempt on Hitler in Switzerland, to spying on the Japanese in Manchuria, and helping the Soviet Union build the atom bomb, Sonya conducted some of the most dangerous espionage operations of the twentieth century. Her story has never been told - until now.

Agent Sonya is the exhilarating account of one woman's life; a life that encompasses the rise and fall of communism itself, and altered the course of history.