A change in approach, with a sort-of thriller in the near future, following an experimental army unit preparing to use a secret and terrible weapon.  But much of the story is about love, and Amis abandons irony while exploring whether the existence of God can be reconciled with the existence of suffering.  

References

R D Laing The Divided Self (1961)

John Robinson Honest to God (1963)

Dylan Thomas "A Refusal to Mourn the Death, By Fire, of a Child in London"

Father Ted "That would be an ecumenical matter"

Wee Gwen (British Tactical Nuclear weapon)