FELLOW PASSENGER, by Geoffrey Household (271 pp.; AtlanticLittle, Brown; $3.50).
This is another dance around the atom bomb, but unlike Authors Snow and Bourjaily (see above), Novelist Household has left aside the moral self-torture and told a rattling good story. The ancient English manor house of Moreton Intrinseca has become a hostel for scientists working on The Bomb. But in Ecuador, his dying father has told Claudio Howard-Wolferstan that "certain assets" are hidden up an old attic chimney in the ancestral mansion. Barred from lawful entry by ultra-strict security rules, Clubman Claudio climbs the wall one night, vainly searches an attic...