If you have any interest in British Scientific Intelligence during WWII then the book to read is Most Secret War by Prof, Reginald Victor Jones. It was his responsibility to anticipate the German applications of science to warfare, so that we could counter their new weapons before they were used. It chronicles the Battle of the Beams, Radar, V1 Flying Bombs and VII Rockets and Germany's tentative steps towards a nuclear bomb. Gripping stuff that's not too technical.
