The true story of Secret Agent Yeo-Thomas, as told here, might easily have been used as the basis for a thrilling adventure tale of espionage. But as Bruce Marshall, who served in Intelligence in the British army in World War II, has chosen to tell it, this might be defined as the factual record behind the melodrama of events. For here we follow the stops by which the Wing-Commander of the R.A.F. became Britain's foremost operator. His mission was to bring unity to the underground forces in France; his problems involved the control of the Communist directives from outside France, while at the same time using to the fill the forces of Resistance on all levels. He was Enemy No. I of the Gestapo, and yet- after being imprisoned and tortured, he escaped death- and eventually escaped, took on the identity of another prisoner, was recaptured, transferred and finally escaped again. The elements of the story themselves make it absorbing reading, though the telling has muted the sensational aspects.