In 1957 the Australian-American composer Percy Grainger, then 75 and in failing health, received a letter from another pianist-composer, the young Ronald Stevenson, writing from his home in West Linton, below Edinburgh. That first contact - requesting Grainger's reminiscences of Ferruccio Busoni, with whom he had studied - led to an exchange of 32 letters over the four years before Grainger's death in February 1961. The two men soon found that, despite their 46-year age-difference, they had many affinities. Both were pianists of staggering abilities and composers who combined a love for...