Frederik Pohl

Roger Torraway watched in horror as the monster lurched, toppled over and died. Project Man Plus had gone suddenly and drastically wrong. The race to colonize Mars was too important, too costly, and America was already too committed, for plans to be scrapped. They would have to make a new Martian. And Roger Torraway was it, candidate for the endless surgery, operation after painful peration, that would enable him to survive on that faraway planet....

In Book Two of the Heechee Saga, Robinette Broadhead is on his way to making a fortune by bankrolling an expedition to the Food Factory--a Heechee spaceship that can graze the cometary cloud and transfor the basic elements of the universe into untold quantities of food. But even as he gambles on the breakthrough technology, he is wracked with the guilt of losing his wife, poised forever at the "event horizon" of a black hole where Robin had abaondoned...

Humans who dream of life among the stars are joining the Heechee at the core, to live there along with those humans and Heechee whose minds have been stored in electronic memory so that their wisdom may survive the death of their physical bodies.