The title is the antonym of ""explosion"" and the big idea fumbled with here is that of a population implosion. In the fall of 1971, a most effective pesticide introduced into the water supply left 85% of England's female population sterile. The fertile 15% become, therefore, a national resource to be husbanded breeding stock stimulated to produce twins, trips and quads from Grade A sperm. Bart, the Minister of Health, is an organizational genius who erects a structure of Mums camps, confines his own wife when she turns out to be one of the capable few and psychs the country into accepting the deal. None embrace the plan more passionately than his lovely Julia. After eighteen children born over a five year period, Julia begins to suspect that it's all inhuman and escapes from her Mum pen to find Bart dallying with her identical, but sterile, twin. It's not at all porny; it's dry as a demographic report?. The. . . er. . . conception is boundless, but the writer is limited.