Fair Coin by E. C. Myers

Ephiram Scott's life is in a rut when he discovers a dead boy who looks exactly like him--so much so that Ephiram's mother thought Ephiram was the one who got run over by a bus. What's more, Ephiram's twin came into the morgue with a strange coin: Make a wish and flip it. If the coin comes up heads, Ephiram's wish comes true. If it lands on tails, he still gets what he wished for, but with terrible results. Ephiram can try to set things right, but only by risking another wish.

E. C. Myers' Fair Coin is a book about hasty wishes and unintended consequences. It will call to mind--and even name-checks--W. W. Jacobs' short story "The Monkey's Paw." But while Jacobs' story is fairly straightforward, Fair Coin starts simply enough but slowly grows more and more complex as parallel worlds and parallel lives begin to pile up. In this way, it calls to mind some of the best, most mind-bending fiction of Philip K. Dick or Jorge Luis Borges.

Fair Coin is cerebral science fiction with enough romance and two-fisted action to keep it from getting too bogged down in its own ideas. A great read for just about anyone.