The marimba is rapidly achieving greater importance as a solo percussion instrument. Solo compositions for the marimba have been commissioned and performed only in the last sixty years. The 1986 National Endowment for the Arts Solo Marimba Commission is considered one of the most important commissioning projects in the history of marimba literature. Two compositions created through this project, Velocities by Joseph Schwantner and Reflections on the Nature of Water by Jacob Druckman have become two of the most influential works in contemporary marimba music. This thesis will focus on a historical perspective of the project, as well as theoretical aspects and performance issues related to these two compositions. The National Endowment for the Arts (NEA) issued a consortium commissioning grant through the Percussive Arts Society (PAS) in 1986 to three internationally renowned marimbists, William Moersch, Leigh Howard Stevens and Gordon Stout. Three Pulitzer Prize winners were brought together to compose three new works for the marimba. The resulting pieces were: Reflections on the Nature of Water by Jacob Druckman, Velocities by Joseph Schwantner, and Islands from Archipelago: Autumn Island by Roger Reynolds. A brief history of the classical concert marimba and the development of solo marimba literature is provided in the second chapter. The fourth and fifth chapters provide individual information about the pieces, including concise biographical information about the composers and an analysis of the two compositions.