Bach, whose seminal book of preludes and fugues called The Well-tempered Clavier (in German, Das wohltemperierte Klavier) is often cited as the pivot point beyond which older mean-tone and ancient just intonation tunings were abandoned (in the late-18th century) and the then-future of Western Classical (and popular) instruments were (and most are still) based, for exploitation of all 24 theoretical key signatures.

Partch's earliest compositions were small-scale pieces to be intoned with simple folkloric-like string instrumental backing; his later works were large-scale (like a fusion of theater and music decidedly related to but quite apart from Wagnerian opera), they were integrated theater productions in which he expected each of the performers to sing, dance, speak, and play instruments in a "corporeal apotheosis"[clarification needed].

He took to self-study in San Francisco's libraries, where he discovered Hermann von Helmholtz's Sensations of Tone, which convinced him to devote himself to music based on scales tuned in just intonation.

[4] In 1923 he came to reject the standard twelve-tone equal temperament of Western concert music when he discovered a translation of Hermann von Helmholtz's Sensations of Tone.

[6] By 1925, Partch was putting his theory into practice by developing paper coverings for violin and viola with fingerings in just intonation, and wrote a string quartet using such tunings.

A private group of sponsors sent Partch to New York in 1933, where he gave solo performances and won the support of composers Roy Harris, Charles Seeger, Henry Cowell, Howard Hanson, Otto Luening, Walter Piston, and Aaron Copland.

[8] He met musicologist Kathleen Schlesinger, who had recreated an ancient Greek kithara from images she found on a vase at the British Museum.

[11] Partch returned to the U.S. in 1935 at the height of the Great Depression, and spent a transient nine years, often as a hobo, often picking up work or obtaining grants from organizations such as the Federal Writers' Project.

After taking some woodworking courses in 1938, he built his first Kithara[10] at Big Sur, California,[8] at a scale of roughly twice the size of Schlesinger's.

[8] He was staying on the eastern coast of the U.S. when he was awarded a Guggenheim grant in March 1943 to construct instruments and complete a seven-part Monophonic Cycle.

On April 22, 1944, the first performance of his Americana series of compositions was given at Carnegie Chamber Music Hall put on by the League of Composers.

This was a productive period, in which he lectured, trained an ensemble, staged performances, released his first recordings, and completed his book, now called Genesis of a Music.

[13] In 1949, pianist Gunnar Johansen allowed Partch to convert a smithy on his ranch in Blue Mounds, Wisconsin into a studio.

[15] In early 1951, Partch moved to Oakland for health reasons, and prepared for a production of King Oedipus at Mills College,[15] with the support of designer Arch Lauterer.

[b][15] In February 1953, Partch founded a studio, named Gate 5, in an abandoned shipyard in Sausalito, California, where he composed, built instruments and staged performances.

[15] Partch's three Plectra and Percussion Dances, Ring Around the Moon (1949–1950), Castor and Pollux, and Even Wild Horses, premiered on Berkeley's KPFA radio in November 1953.

[16] Though these two works were based, as King Oedipus had been, on Greek mythology, they modernized the settings and incorporated elements of popular music.

[18] His final theater work was Delusion of the Fury,[16] which incorporated music from Petaluma,[14] and was first produced at the University of California in early 1969.

[19] The same year, a second edition of Genesis of a Music was published with extra chapters about work and instruments Partch made since the book's original publication.

Partch sought to bring vocal music back to prominence, and adopted tunings and scales he believed more suitable to singing.

[23] 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.

This allowed for a larger number of smaller, unequal intervals than found in the Western classical music tradition's twelve-tone equal temperament.

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.

[23] Partch uses the terms Otonality and Utonality to describe chords whose pitch classes are the harmonics or subharmonics of a given fixed tone.

[34] Genesis of a Music has been influential on later generations of composers interested in new intonational systems, such Ben Johnston and James Tenney (both of whom worked with Partch in the 1950s).

[36] His non-Western orientation was particularly pronounced—sometimes explicitly, as when he set to music the poetry of Li Bai,[37] or when he combined two Noh dramas with one from Ethiopia in The Delusion of the Fury.

Partch used the words "ritual" and "corporeal" to describe his theatre works—musicians and their instruments were not hidden in an orchestra pit or offstage, but were a visual part of the performance.

In Seventeen Lyrics of Li Po for the Adapted Viola, Partch "doesn't bother with rhythmic notation at all, but simply directs performers to follow the natural rhythms of the poem.

[26] In 2012 a complete set of replicas was built by Thomas Meixner under commission by Ensemble Musikfabrik and used in performances of Partch's work including Delusion of the Fury.

[45] Partch's later works were large-scale, integrated theater productions in which he expected each of the performers to sing, dance, speak, and play instruments.