Time Enough for Love

Time Enough for Love is a science fiction novel by American writer Robert A. Heinlein, first published in 1973. The book made the shortlist for the Nebula, Hugo and Locus awards for best science fiction novel of that year, although it did not win. It did win a retrospective Libertarian Futurist Society award: the Prometheus Hall of Fame award for 1988.

The book covers several periods from the life of Lazarus Long (born Woodrow Wilson Smith), an early beneficiary of a breeding experiment designed to increase mankind's natural lifespan. The experiment is known as the Howard Families, after the program's initiator. Lazarus is more the result of a mutation than the breeding experiment, and he is the oldest living human at more than two thousand years old.

The first half of the book takes the form of several novellas connected by Lazarus's retrospective narrative. In the framing story, Lazarus has decided that life is no longer worth living, but, in what is described as a reverse Arabian Nights scenario, agrees not to end his life for as long as his companion and descendant, chief executive of the Howard Families Ira Weatheral, will listen to his stories.

This story concerns a 20th-century United States Navy seaman, midshipman, and officer David Lamb, who receives multiple promotions while minimizing any semblance of real work or combat by applying himself enthusiastically to the principle of "constructive laziness".

Lazarus tells of his visit as an interplanetary cargo trader to a planet, where he bought a pair of slaves, brother and sister, and immediately manumitted them. Because they had no knowledge of independent living or any education, Lazarus teaches them "how to be human" during the voyage.

The two were the result of an experiment in genetic recombination in which two parent cells were separated into complementary haploid gametes and recombined into two embryos. The resulting zygotes were implanted in a woman and gestated by her, with the result that although both have the same surrogate mother and genetic parents, they are no more closely related genetically than any two people taken at random. They have been prevented from sexual relations by a chastity belt. However, having confirmed that there is no risk of genetic disease in their offspring (described as the only valid argument against incest), Lazarus solemnizes their marriage and later establishes them as the owners and operators of a thriving business. At the end of the story, he reveals that the twins looked the same age decades later and expresses his belief that they were his own descendants, from an earlier time that he had been a slave on the same planet.

A short scene-setter introduces a planet on which Lazarus has led a group of pioneering colonists.

Lazarus, now working as a banker and shopkeeper on the frontier planet and keeping his true age secret, saves a young girl, Dora, from a burning house and becomes her guardian. When she becomes an adult, he leaves the area but returns as a younger man and marries her, and the two move away to start a new settlement, where Lazarus' long life is less likely to be noticed. They eventually manage to build a thriving community. Because Dora is not a descendant of the Howard Families, the source of his longevity, she eventually dies of old age, leaving Lazarus to mourn.