This dissertation is a study of the styles shown in Reubke's The 94th Psalm. As a student of Hermann Bonicke, Theodor Kullak, and Adolf Marx, Reubke was trained in the masters of the Baroque and Classical traditions. Written after his study with Franz Liszt in the newer style, The 94th Psalm is a crystallization of these various influences into his own personal style, a remarkable achievement at age twenty three. It is a synthesis of two different styles of organ music at the time; the traditional and conservative represented by Mendelssohn and Schumann, and the progressive by Liszt. Reubke's unique approach to the sonata fomi in the "double function" unified three individual movements into one musical entity by the use of the cyclic theme. The harmony and the tonality are advanced and anticipate the late nineteenth-century style. As the first programmatic organ music in the nineteenth century, The 94th Psalm is an idiomatic organ work which employed the virtuoso piano technique of the time. In spite of Reubke's young age, The 94th Psalm demonstrates his great maturity. His wish to express himself is realized in the work in profound depth and imagination. Through the psalm text he poured out his mind and soul with tremendous energy. In addition to the prevailing concept of the dominant influence of Liszt on the work, the study discusses in detail other aspects which are equally significant to The 94th Psalm, particularly the classical organ tradition of the time and Adolf Marx's influence. After the introduction in Chapter I, Chapter II describes Reubke's family, his life including musical training and his works. Chapter II discusses the influences on The 94th Psalm; organ composition of the mid-nineteenth-century Germany, the influential teachers and their works. Chapter IV presents an analysis of the work, the programmatic feature, the characteristic harmony, and the cyclic use of the theme. Chapter V deals with the performance of The 94th Psalm: the characteristics of the mid-nineteenth-century organ in Germany, the registration, dynamic and expression marks, and published editions. The final Chapter VI is a conclusion.