Mr. Barlow's novel begins as if a wide, philosophical investigation of man in the nuclear age were his subject. The reader girds himself and gets his thinking cap ready. However, the cap is never needed--only the usual amount of good will toward a story. For The Hour is about a Communist conspiracy in London to get the directional signal component of an anti-missile missile, and to recover a defected Soviet scientist. In the large, it is also about the motives for treason. What distinguishes the story from claptrap is a solemn lack of melodrama and the rendering of the characters in the round. Four Britons, two girls and two men, turn traitor for the simplest, most believable reasons: God, love, recognition and money. Each cozily tucks his guilt out of sight. The plot (there's no point in giving it away) builds to no great tension anywhere, and there is no ""the"" hour of maximum danger: the title is background music. Characters include a stunning model and a dashing terror of a blackmailer, (pornographic pictures of the women he seduces), a wonderfully crazy telephone operator, a hard-up student poet who hates Negroes, the defected scientist, a Soviet major, a police investigator and a poor dupe who has lost faith in the Christian Doorstep movement (pamphlets printed in Illinois). They are all well-modelled and passably absorbing. The author himself, however, seems greatly to measure them by whether or not they believe in God! That's new.