Scriabin`s output is often split into three periods.: Op. 1-29 (1886-1901), Op. 30-57 (1903-1908), and Op. 58-74 (1910-1914). He made a gradual transition to atonality, beginning as early as 1903. It is precisely between the second and third periods when we begin to observe a significant shift taking place in Scriabin`s way of conceiving his music. The purpose of this paper is to document the decline of tritone in Scriabin`s music primarily found in the transitional part of the composer`s musical career. While the theory was formulated by Russian music theorists, it has had a direct influence on various ways of understanding Scriabin`s complicated later works. The second chapter deals with the tritone in Scriabin`s transitional period. The most important harmonic function in Scriabin`s transitional music is a ♭Ⅱ-Ⅴ progression. The third chapter explores Scriabin`s music from the viewpoint of Russian music theory. I focus primarily on the work of three Russian theorists, namely, Yavorsky, Dernova and Kholopov, and how their works are related to the tritone of Scriabin`s music. Both Dernova and Kholopov carry over Yavorsky`s theory when discussing Scriabin`s problematic compositions, and one gets the sense. The merit of Russian music theory lies in the methodology. In particular, Scriabin`s Poeme, Op. 59, No. 1 is examined by using Russian music theorists`s views. The Russian theorists offer a new system of analysis, thereby allowing us to have an intimate and perspicuous understanding of the late Scriabin`s mechanics.

In the early twentieth century, many eastern European composers show the pervasive absorption of structural melodic characters of folk sources into more abstract contemporary music idioms. Pitch structure in that century music has become more explicit in recent analytic writings. Scriabin derived his compositional materials from more abstract sources that were identical to those found in the folk sources. Scriabin moved towards an increasingly systematic handing of pitch set constructions. This paper proposes a theoretical model for a study of collection in post tonal music. It is the aim of this paper to focus on collection in Scriabin's Op. 58, Feuillet d'album(1909). His output is often split into three periods. : Op. 1-29, Op. 30-57, and Op. 58-74. Op. 53-58 pieces are of primary importance in Scriabin's transition to atonality. It is precisely between the second and third periods that something very important happened in Scriabin's musical mind. In particu]ar, his Op. 58 was written while Scriabin was composing Prometheus. The composition employs 6-34 : in a sense the piece is a study of the properties of 6-34, with which Scriabin wad the preoccupied. The most famous variety of this chord is known as the Mystic, or also as the Prometheus as it is ubiquitous in that work. It should be emphasized that Scriabin's small pieces stand in a special relationship to his larger works. Thus the links between his last are strong, as will be seen in the course of this paper.