In 1879, French amateur composer Edmond de Polignac (1834-1901) painstakingly devised a new way to create melodies and harmonies using a scale that alternated half and whole steps. This scale-known today as octatonic-was an important element in the music of Liszt and Rimsky-Korsakov, and would later figure prominently in the works of Ravel, Stravinsky, and many others. Sylvia Kahan, author of Music's Modern Muse: A Life of Winnaretta Singer, Princesse de Polignac, here publishes the Prince's octatonic treatise for the first time-in both the original French and in English translation-and comments extensively on what the treatise, and the Prince's little-known compositions, reveal about musical thought in late nineteenth-century Paris. Given his aristocratic lineage, Polignac might seem an unlikely precursor of musical modernism, yet he was known as an advocate of "advanced ideas." Late in life, he married wealthy heiress Winnaretta Singer, who sponsored prestigious public concerts of her husband's bold works, interpreted by the greatest musical artists in Paris. Debussy and FaurA(c) were admirers of Polignac's music, especially the 1879 octatonic oratorio Pilate livre le Christ (Pontius Pilate Hands Christ Over). Marcel Proust lauded his compositions and the "essence of genius of their author." In Search of New Scales is based on bibliographic material in private archives, as well as letters and other documents in the BibliothA]que Nationale de France. Sylvia Kahan's new book will become a permanent point of reference for all future studies of post-Romantic and twentieth-century composition. Sylvia Kahan is professor of music at the Graduate Center and College of Staten Island, City University of New York. Her previous book, Music's Modern Muse, is published by the University of Rochester Press in hardcover and paperback.