Seventh Son, by Orson Scott Card is the first volume in the alternative history / Fantasy series "The Tales of Alvin Maker".

The first five chapters of this novel appeared in "Isaac Asimov's Science Fiction Magazine" in 1986 as the Short Story "Hatrack River".

Alvin is a Seventh Son of a Seventh Son and as such a very rare person indeed. So rare in fact that he maybe the only one of his kind in the world. Seventh Sons have power, a Seventh Son of a Seventh Son has that power in much greater magnitudes.

Alvins abilities make him the target of the Unmaker, who recogizes that the power may be that of a Maker, in fact maybe the second ever to exist, and it had been a long time since the first had walked on water and turned water to wine...