[j. d. worthington]

On the ending to the novel, as well as the donor being there at the right place at the right time... I'd say that ties into a theme that runs throughout Heinlein's career, since at least Beyond This Horizon, a combination of life being "the only game in town" (and handled like an enormous gambling game) and metempsychosis that links it with Horizon, Red Planet, Stranger in a Strange Land, and even elements of Methuselah's Children, not to mention his later novels....