Malachi Constant, "the richest man in America, " gives up his indulgent lifestyle to follow an urgent calling to probe the depths of space. He participates in a Martian invasion of Earth, mates with the wife of an astronaut adrift on the tides of time, and follows the lure of the "Sirens of Titan."

Three thousand years after Earth's colonisation of the planet Borthan, stories of self-serving hypocrisy that occurred among the first arrivals have bred a culture that forbids emotional sharing and denies the naturally human concept of 'self'. The result is a lasting peace, but at a terrible price. For it is a peace without love, without self, where even the mention of the word 'I' is taboo. Spurred on by the arrival of an Earthman with a self-baring...