Methuselahs Children

by Robert A. Heinlein

Starting off a grocer, Ira Howard became rich as a sutler wholesaler during the American War of the Secession but died of old age at 48 or 49 years old. The trustees of his will carried out his wishes to prolong human life by financially encouraging those with long-lived grandparents to marry each other and have children. By the 22nd century, the "Howard families" have a life expectancy exceeding 150 years and keep their existence secret with the "Masquerade" in which the members fake their deaths and obtain new identities.

The Masquerade helped the Families survive the dictatorship of Nehemiah Scudder, but as an experiment, some Howard members reveal themselves to The Covenant, hoping that the free society established after Scudder's defeat will be friendly. They are mistaken since others refuse to believe that the Families obtained their lifespan by selective breeding but insist that they have developed a secret method to extend life. Administrator Slayton Ford, leader of Earth, believes that the Families are telling the truth, but cannot prevent efforts to force Howard members to reveal their alleged rejuvenation abilities.

Lazarus Long, the eldest member of the Families, proposes that the Families hijack the colony starship New Frontiers to escape Earth. Using an inertialess drive invented by Howard member Andrew Jackson "Slipstick" Libby, the Families leave the Solar System with the deposed Ford. The first planet they discover has humanoid inhabitants domesticated by indescribable godlike natives. When Earthly humans prove incapable of similar domestication, they are expelled from the planet.

The second planet is a lush environment with no predators and mild weather. Its inhabitants are part of a group mind, with the mental ability to manipulate the environment on the genetic and molecular level but do not distinguish between individuals. That becomes evident when Mary Sperling, the second oldest of the Families, joins the group mind to become immortal. The Families are further horrified when the group mind genetically modifies the first baby born on the planet into a new, alien form. A majority of the Families returns to Earth to demand their freedom; Libby, with the help of the group mind, builds a new faster-than-light drive to take them home in months instead of years.

The Families, returning to the Solar System 74 years after their original departure because of time dilation, discover that Earth's scientists have artificially extended human lifespan indefinitely by replicating what they believe is the Families' secret. The Howard members are now welcomed for their discovery of travel faster than light. Libby and Long decide to recruit other members of the Families and explore space with the new drive.