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Man Plus is a 1976 science fiction novel by Frederik Pohl. It won the Nebula Award for Best Novel in 1976 and was nominated for the Hugo Award for Best Novel in 1977. Pohl teamed up with Thomas T. Thomas to write a sequel, Mars Plus, published in 1994.

Plot introduction:

In the not too distant future, a cold war threatens to turn hot. Colonization of Mars seems to be mankind's only hope of surviving certain Armageddon. To facilitate this, the American government begins a cyborg program to create a being capable of surviving the harsh Martian environment...Man Plus. After the death of the first candidate, Roger Torraway becomes the heart of the program.

In order to survive in the thin Martian atmosphere, Roger Torraway's body must be replaced with an artificial one. At every step he becomes more and more disconnected from humanity, unable to feel things in his new body. It is only after arriving on Mars that his new body begins to make sense to him. It is perfectly adapted to this new world, and thus he becomes perfectly separated from his old world, and from humanity.

The success of the Martian mission spurs similar cyborg programs in other space-faring nations. It is revealed that the computer networks of earth have become sentient, and that ensuring humanity's survival will guarantee theirs as well. In the end, the network is puzzled...it appears that something else was behind the push to space, a mystery even to the machines.