(Beacham's Encyclopedia of Popular Fiction)

Clarke is not especially interested in creating characters of great complexity. The Reinhold and Conrad of the "Prologue" suggest Wernher von Braun and Stormgren Trygve Lie. Jean and George are purposefully made conventional young adults; her paranormal ability is due to her children, not herself. Even Jan, the most self-willed character, is outstanding only because of his youth. In their various normalities these characters illustrate the theme of isolation. What is remarkable is Clarke's division of them into two groups, the questers and the midwives. Stormgren relies upon the blind Welshman and Duvall, Jan on Jean and Sullivan, the children on Salomon and George, and the Overmind on the Overlords. Thus Clarke reiterates in great detail the themes of transcendence and impotence.

The most impressive character is the Overlord Karellen. His fascination does not end when his Satanic appearance is revealed, but continues through the problem of the Overlords' purpose on Earth; thus the rhythm of the novel depends upon the series of transformations that the alien identity moves through: hidden god, demon, technocrat, parent, gelding. Much of the resonance of the novel depends on the fact that none of these identities is quite superseded by any of the others. Thus the human stereotypes become complexly related in the character of Karellen.

(The entire section is 212 words.)