There are many books on counterpoint and harmony, but few indeed on the theory of rhythm. Those few approach it through its graphic notation, or in terms of metrical feet, as if it were poetry. Maury Yeston treats rhythm instead in the context of sounded music, with a view to clarifying its ambiguous and little studied, but crucial, relationship with pitch. Although his work is strongly influenced by the methods of the German theorist Heinrich Schenker, it is a strikingly original contribution to musical theory in its own right. Maury Yeston begins by developing analytic procedures for understanding the rhythm of tonal music in terms of pitch levels. He then focuses on certain structures that arise from the interaction of these levels, thereby discovering some fundamental aspects of logical form in the system of musical rhythm. In the course of the inquiry, Mr. Yeston redefines traditional notions of meter, syncopation, and accent. In addition, his study provides a basis for understanding the relationships by which unique rhythmic designs are integrated aesthetically in a cohesive musical composition.