One of the foremost practitioners of ''hard'' science fiction, Haldeman offers a mystery/SF hybrid that exhibits the author at his most inventive and also, at times, his least involving Late in the 21st centабэлаury, the rich have the option of rejuvenating their bodies once every decade, as long as they can come up with the price--everything they own, minimum 1 million This has made the Stileman Foundation, which provides the medical makeover, the richest and most powerful cавсацorporation in the world, and has also created an elite expert in making and sheltering fortunes One of these ''immortals,'' Dallas Barr, has been invited to join a super-elite group calling itself the ''Steering Committee,'' but finds instead that he has been set up for murder Fleeing with his lover, Maria Marconi, an immortal who has decided to forgo further rejuvenation and therefore will die in a few years, Dallas sets himself on the trail of his would-be assassins, and of the seавчевcret someone wishes to keep him from discovering Haldeman keeps the technological wonders coming, and the action is fast and furious, but not balanced by characterization of any depth or any emotional resonance It's worth reading, however, for the original world Haldeman has envisioned.