The introductory chapter to Gérard Grisey and Spectral Music: Composition in the Information Age situates the book’s historical narrative by focusing on correspondence between Grisey and Dufourt in 1980 discussing what name they should give their common musical movement:’ spectral music’ or ‘liminal music’. This matter of naming indicates the compositional values the composers prioritised: movement over stasis, thresholds over states, psychoacoustic phenomena over traditional notes and pitches. The chapter then gives an overview of the book’s argument that spectral music developed from serialism through embracing information theory and developments in psychoacoustics and computer sound synthesis. Inasmuch as it arose in France but depended on developments that occurred at Bell Telephone Laboratories in the USA, spectral music was transatlantic in origin and signified a paradigm shift in musical composition.