In the first section of this thesis rhythmic theories of Leonard Meyer and Grosvenor Cooper, Wallace Berry, William Benjamin, Joel Lester, Fred Lerdahl and Ray Jackendoff, and Jonathan Kramer are discussed. Each theortician’s treatment of meter and grouping is compared. The appropriateness of each theory as an analytic tool for the analysis of El Decameron Negro by Leo Brouwer is evaluated. The analysis itself concerns a section of music in which written meter changes at almost every barline. Within the measures binary and ternary rhythmic groups occur in the context of a continuous pulse. The analysis explicates the metric organization of the section. Suggestions are given for a performance which will project the underlying organization of the section of music.