Erwin Stein (7 November 1885 – 17 July 1958) was an Austrianmusician and writer, prominent as a pupil and friend of Schoenberg, with whom he studied between 1906 and 1910. He was one of Schoenberg’s principal assistants in organizing the Society for Private Musical Performances. In 1924 it was Stein to whom Schoenberg entrusted the delicate as well as important task of writing the first article – Neue Formprinzipien ('New Formal Principles') – on the gradual evolution of what was soon to be explicitly formulated as 'twelve tone technique'. Until 1938 he lived in Vienna, where he was respected as a music teacher and conductor as well as a writer active on behalf of the music and composers he valued.
His books include Orpheus in New Guises (a collection of writings from the period 1924-1953) and Form and Performance (1962). He was the editor of the first collection of Schoenberg's letters (Germany 1958; UK 1964). He was also instrumental in setting up the modern music periodical Tempo in 1939.