New Musical Resources is a book written by Henry Cowell in 1919, unpublished until 1930. In it, Cowell proposes a theory of musical relativity in which pitch, rhythm, and the progress of music history are grounded through reference to the structure of the overtone series: the "living essence from which musicality springs." Ethnomusicologist Charles Seeger encouraged a young Cowell to rationalize the compositional tools he had been developing, which ultimately led to the creation of this book.
In the book’s first section, Cowell presents the development of Western harmony as progressive upward movement through the overtone series. He suggests the continuation of this same logic into chords based on the ratios beyond the minor seconds that he was using to create "cluster chords." His rhythm chapter proposes the whole-note as the basic unit of time, encouraging division beyond the standard multiples of two into the next numbers in the harmonic series—creating third-notes, fifth notes, etc. This method enables the composition of rhythmic patterns that rely on the same ratios as are present between various melodic and harmonic intervals. Many American composers—notably Conlon Nancarrow—have utilized Cowell’s concepts, which predate the development of similar ideas in integral serialism by several decades.
