Partch made public his theories in his book Genesis of a Music (1947). He opens the book with an overview of music history, and argues that Western music began to suffer from the time of Bach, after which twelve-tone equal temperament was adopted to the exclusion of other tuning systems, and abstract, instrumental music became the norm. Partch sought to bring vocal music back to prominence, and adopted tunings and scales he believed more suitable to singing.  Inspired by Sensations of Tone, Hermann von Helmholtz's book on acoustics and the perception of sound, Partch based his music strictly on just intonation. He tuned his instruments using the overtone series, and extended it past the twelfth partial. This allowed for a larger number of smaller, unequal intervals than found in the Western classical music tradition's twelve-tone equal temperament. Partch's tuning is often classed as microtonality, as it allowed for intervals smaller than 100 cents, though Partch did not conceive his tuning in such a context. Instead, he saw it as a return to pre-Classical Western musical roots, in particular to the music of the ancient Greeks. By taking the principles he found in Helmholtz's book, he expanded his tuning system until it allowed for a division of the octave into 43 tones based on ratios of small integers.  Partch uses the terms Otonality and Utonality to describe chords whose pitch classes are the harmonics or subharmonics of a given fixed tone. These six-tone chords function in Partch's music much the same that the three-tone major and minor chords (or triads) do in classical music. The Otonalities are derived from the overtone series, and the Utonalities from the undertone series.

Answer this question "what was included in the book?" by extracting the answer from the text above.
He opens the book with an overview of music history, and argues that Western music began to suffer from the time of Bach,