The Harvest is Robert Charles Wilson's sixth novel. The first aliens to contact Earth, mysterious beings called the Travellers, bring the gift of immortality to those humans who choose to accept it—and the price it exacts. While most people leap at the chance to live forever, even at the cost of their humanity, a few hold on to their mortality and find themselves the inheritors of a strangely transformed future.
References
The Harvest (1992 novel) Wikipedia(Text) CC BY-SA