Starting in 1902 at a country school that had an enrollment of fourteen, Frank Boyden built an academy that has long since taken its place on a level with Andover and Exeter. Boyden, who died in 1972, was the school's headmaster for sixty-six years. John McPhee portrays a remarkable man "at the near end of a skein of magnanimous despots who...created enduring schools through their own individual energies, maintained them under their own absolute rule, and left them forever imprinted with their own personalities." More than simply a portrait of the Headmaster of Deerfield Academy, it is a revealing look…