A nice guy immersed in music hardly seems a hot property but first Arnold Dobrin (1967, 701, J-257) and now Catherine Peare have made Aaron Copland's commitment tangible and interesting. Dobrin's is the older (13+) and wiser book but Miss Peare's naive enthusiasm applied to her usual competent narrative engages the reader on a different level and masks the uneventfulness of Copland's personal life. While he battens on the piano, discovers that New York is a perpetual concert, finds the ideal teacher (Boulanger) and a prime patron (Koussevitzky) in Paris, she provides a continuous briefing on the elements, the forms, the history of music. The latter years are compressed into a chronology of compositions and, briefly, the circumstances attending them: The Second Hurricane for the children at the Henry Street Settlement, El Salon Mexico, the fruition of friendship with Carlos Chavez and exposure to Mexican folk music; Billy the Kid and Rodeo, all-American ballets; A Lincoln Portrait and Appalachian Spring, similarly indigenous. It's a popular repertoire aggreeably introduced, with a list of representative works appended.