Books & artsBook reviewEspionageThe Fuhrer’s man in ManhattanRing of Spies.By Rhodri Jeffreys-Jones.As Germany pursued its territorial expansion in 1938, many Americans wanted nothing more than to be left alone.President Franklin Roosevelt had signed three neutrality acts forbidding involvement in Europe’s troubles.Of the fears that kept his compatriots awake, Hitler was eclipsed by mobsters, dust bowls and unemployment.This was to change, explains Rhodri Jeffreys-Jones in his new book,when the FBI’s unveiling of a Nazi spy ring poisoned relations with Germany and forced America to confront a hostile world.A historian at Edinburgh University, Mr Jeffreys-Jones draws the reader in with thrilling, but initially disparate, tales of German espionage.The sense of Nazi audacity steadily rises.A widow with a penpal in Hamburg suddenly develops a penchant for photographing naval bases.A group of agents smuggle out secret documents as stamp-size pictures hidden in pocket-watches.Another cell plots to snatch mobilisation plans by subduing a colonel with a sedative-loaded fountain pen.