In a sense, this massive chronicle of the life and interminable times of Lazarus Long, the oldest member of the human race (who first appeared in Methuselah's Children, 1958), is the conclusion of Heinlein's famous future history series of the '40's and '50's. But in style and world view it belongs not with the tightly plotted early adventures but with the later novels like Stranger in a Strange Land and I Will Fear No Evil, combining a great deal of unexplicit sex with very explicit philosophizing on everything from government to relations between men and women. At the age of some 2000, Lazarus is ready to commit suicide, but the Chairman of the genetically long-lived Howard families is determined to keep him alive to preserve his wisdom. In the process of learning to appreciate life again, Lazarus helps found a new colony, joins a group marriage, encounters (and beds) a computer who has decided to become a woman, brings up (and beds) twin girls who are female clones of himself, travels back in time and meets (and beds) his mother, spins numerous tales of his past adventures and generally enjoys himself hugely. SF's grand old man still has energy, verve and a genius for making outrageous premises, say the advisability of incest, seem perfectly reasonable. His devotees, and they are legion, will find this irresistible.