The art of the piano is a study in evolution — of both an instrument and of human talent. Among us there have been a rare few whose gifts included the physical dexterity, the innate musicality and the creativity to make the instrument sound brilliant; Mozart did it first, and, more recently — as Stuart Isacoff notes in his new book, A Natural History of the Piano — so has jazz great Oscar Peterson. In this historical tribute to the piano, the founding editor of Piano Today