Roger Huntington Sessions (December 28, 1896March 16, 1985) was an American composer, teacher, and writer on music. He had initially started his career writing in a neoclassical style, but gradually moved further towards more complex harmonies and postromanticism, and finally the twelve-tone serialism of the Second Viennese School. Sessions' friendship with Arnold Schoenberg influenced this, but he would modify the technique to develop a unique style involving rows to supply melodic thematic material, while composing the subsidiary parts in a free and dissonant manner.
Provided by Wikipedia