This is one of the first novels in Robert Silverberg's "literary" period. With several novels, Silverberg used the strophes of science fiction to explore human values. At the time, fans were furious. Today, such novels may even be the norm in the field. In any case, this novel explores the nature of pain through a tycoon of pain and pleasure and through a man in constant pain who no longer sees himself as human after an alien surgery has altered his looks. There are elements of the Book of Job here, perhaps.