Set on a human-settled world called Parsloe's Planet. The people have become physically and mentally dependent on a local radiation, that emanates from the land. The radiation gradually dissipates over time. As a result, the cities are all mobile and can be airlifted to new locations to take advantage of fresh sources of radiation.
Most of the book isn't, however, about the radiation. It's about the career and personal affairs of Robert Marsden, a professional athlete. We see him change careers several times - from athlete, to an astrologer, to a entertainment producer, and finally a politician. While all of this is going on, he obsesses over an affair he's having with a married woman. Through all of this we explore the post-scarcity society he lives in (basically upper-class 1960s Americans with robots)
The radiation issue doesn't come back until the very end, when society starts to fall …











