Music theorist and musicologist Joseph Yasser, as early as 1951, uncovered progressive tendencies in Rachmaninoff's compositions. He uncovered Rachmaninoff's use of an intra-tonal chromaticism that stands in notable contrast to the inter-tonal chromaticism of Richard Wagner and strikingly contrasts the extra-tonal chromaticism of the more radical twentieth century composers like Arnold Schoenberg. Yasser postulated that a variable, subtle, but unmistakable characteristic use of this intra-tonal chromaticism permeated Rachmaninoff's music.
