Toward the end of this small volume, the author underscores the absolute necessity for solving the major problem of modern times, which is the rapidly widening gap between human population and man's resources. To do so will require severe strictures on the right to breed, but this inevitably will retard the natural rate of human evolution. Perhaps this justifies the central theme of the book, which is that man now has developed an extraordinary capacity to order the direction and rate of his own evolution.
The approach is admittedly speculative. The material ranges over many themes, including conception control, sex determination, human cloning, fetal transplants and surgery, and altering the genetic material through selective chromosomal damage or by viral transformation. The author moves on freely to the more esoteric, such as the possibility of radical extension of the life span, increase of intellect through drugs, information transfusion, direct mind-computer interactions,