Simeon Krug has a vision — and the vast wealth necessary to turn dream into reality. What he wishes is to communicate with the stars, to answer signals from deep space. The colossal tower he’s constructing for this purpose soars above the Arctic tundra, and the seemingly perfect androids building it view Krug as their god. But, Krug is only flesh-and-blood, and when his androids discover the truth, their anger knows no bounds... and it threatens much more than the tower.

Nominated for Nebula Award for Best Novel in 1970.

Nominated for Hugo and Locus Award in 1971.