The distinguished Czech composer Jindich Feld (1925-2007) has composed in all genres of music with the vast majority of his output being chamber and large-scale instrumental works. In recent years, there has been increased interest in Felds compositional language and the theoretical structure of his music composed for the saxophone. However, much of this research focuses on set theory analysis and row usage or general overviews of selected works, not on large-scale formal structures. This document seeks to fill this void by providing a method of analyzing specific movements of Felds post-tonal compositions based on the concepts developed by James Hepokoski and Warren Darcy in their work Elements of Sonata Theory. The central aspect of this document focuses on the interaction of post-tonal musical gestures against the background of the eighteenth- and nineteenth-century sonata form.Elements of Sonata Theory is a comprehensive re-examination of one of the most significant instrumental forms in Western musicsonata formand it examines various aspects of musical energy across action-zones or action-spaces within the context of sonata movements. The type of analysis developed by Hepokoski and Darcy allows for a broad-based and malleable discussion of how composers articulate their musical ideas within the expectations of a rhetorical sonata form. It is this approachthe concept of action zonesthat I believe can be most practical in the discussion of Felds post-tonal sonata forms.Of his numerous works for saxophone, four are significant works in the repertoire and this document focuses on three: the Concerto for Saxophone (1980), Saxophone Quartet (1981), and Sonata for Soprano Saxophone and Piano (1982). The first movements of these three compositions, chosen for their formal organization, compositional content, and overall significance to the saxophone repertoire, will be the focus of this document as these movements clearly show Felds juxtaposition of post-tonal composition procedures within an extremely tonally driven musical structure, i.e. sonata form. The analysis employs the terminology and analytical approach developed within Elements with specific attention paid to:I. Primary Theme ZoneII. TransitionIII. Secondary Theme ZoneIV. Closing Zone