Musicologist; born in Berlin, Germany. After studies in art and music, he held posts in Berlin including curator of the Museum of Musical Instruments. Driven from Germany by the Nazis in 1933, he settled in the U.S.A. four years later and held posts as a consultant to the New York Public Library (1937--52) and a teacher at Columbia University (from 1953). He also served as president of the American Musicological Society in 1948--50. His books include The History of Musical Instruments (1940) and The Commonwealth of Art (1946).