Reese is mainly famous for his groundbreaking work on medieval and Renaissance music, particularly with his two publications Music in the Middle Ages (1940) and Music in the Renaissance (1954); these two books remain the standard reference works for these two eras, with complete and precise bibliographical material, allowing for almost every piece of music mentioned to be traced back to a primary source.
He was a founder-member of the American Musicological Society (AMS) from 1934, and president of the organization from 1950 to 1952.
GustaveReese was my dissertation adviser and, though he was most famous of course for his books on Medieval and Renaissance music, he was always interested in new music as well, and I ran into him more than once at a concert of recent music.
Here, from GustaveReese no less, comes validation for what I�'ve been saying for years, and not only about minimalism being a logical next step in the progress of history.
That Reese could see the logical necessity of a drastic simplification of music in the 1960s, while a thousand academic composers and music professors continue to rail against it, shows up how little music history most composers know.