Planets are for leaving. An Explorer's life and family are on his ship, and once he leaves a planet he will probably never return. Time in space runs at a different rate, so even if he does return to a planet, anyone he knew will have died of old age. If he chooses to stay on a planet, he will never see his family or his ship again, and he will have to adjust to an alien way of life. So the Explorers go on, living in space, and finding new worlds for humans to live on.
NOTE: a shorter version of the book was previously published as ENDLESS VOYAGE.
