David Greenglass, born in 1922 on Manhattan's Lower East Side, was an ordinary machinist whose ideological choices helped arm the Soviet Union with atomic secrets. Assigned to the Manhattan Project at Los Alamos, he passed technical drawings to Soviet couriers through his brother-in-law Julius Rosenberg, becoming an unlikely linchpin of Cold War espionage.

This deep dive is less a spy thriller than a human tragedy about family and self-preservation, culminating in the impossible choice that sent his sister Ethel Rosenberg to the electric chair. It draws on declassified files including the Venona decrypts to reconstruct his path and his ruthless final calculation.

• How wartime panic let a former Young Communist League member get security clearance
• His code names Kaliber and his wife Ruth's designation Wasp in the Venona cab ...