Another P.K.Dick classic. It's been adapted to other media (think Terminator) which will give the reader a leg up on figuring out the ending. But it's still a great read about the hubris of the human race and what happens when our war creations turn against us.
Good short story about how when the vast inhospitable loneliness of the universe and our tenuous small (and somewhat arrogant) human intelligences meet, it's not a mystery who is dominated.
A make up artist who applies semi-permanent skin (usually to disguise criminals) is given a new synthetic skin himself after an "autobath accident scalds him." But the new skin has another agenda than just acting like a protective pelt. How do you escape your own double crossing skin?
Well, we're heading that way. Computers calculating the odds of winning a war, and governments reacting to constantly improve the odds. Earth in the future has discovered she is ringed in by the decadent Alpha Centauri empire which is stifling expansion. If the odds get good enough, Earth can attack Alpha and break out to expand. They are in the process of making a giant bomb to completely eliminate the Alphas. Odds are looking better with this bomb.
Into that mix comes an earth man from the past who is an idiot savant at fixing any electronic circuit and making it work. the computer war odds become confused by this "Variable Man." A giant furball erupts beween the government who wants to eliminate him to stabilize the odds, and scientists who want to protect and use him.
Good twist to the ending. A suspension of some disbelief is necessary to accept the uncanny talents of the variable man.