Spectral music as a school of compositional thought was originally associated with the ensemble l'Itineraire in Paris in the 1970s. Since that time, it has only grown in significance and recognition as it transitioned from concert halls to dance clubs and made other incursions into popular culture. The Oxford Handbook of Spectral Music offers a fully new and expansive understanding of current scholarly and creative activity related to the spectral music movement and its legacy from its founding in the mid-1970's to the current day. The definition of spectral music has been at the center of debate among spectral composers and scholars since Hugues Dufourt first coined the term in the late 1970s. Rather than aiming to present an overarching definition of spectralism, the handbook shows the multiplicity of the spectral legacy by presenting diverse perspectives from top scholars and composers in the field. It includes essays on major founding figures such as Gérard Grisey and Tristan Murail, as well as the proto-spectral practices of Scriabin and Messiaen, and the influences of spectral music on serialism, postmodernism, sound art, and psychedelic rock. It features essays by some of the movement's most significant living composers, such as Steve Lehman, Marilyn Nonken, Ken Ueno, and Patricia Alessandrini. A long overdue examination of an important compositional trend in late 20th century music, this handbook will appeal to scholars, composers, and students desiring to become better acquainted with the broad influence of spectral music: what birthed it, what defines it, and what its future holds in the 21st century.