This dissertation investigates how German-language critics articulated and publicly negotiated ideas about music and expressionism in the first five years after World War I. A close reading of largely unexplored primary sources reveals that "musical expressionism" was originally conceived as an intrinsically musical matter rather than as a stylistic analog to expressionism in other art forms, and thus as especially relevant to purely instrumental rather than vocal and stage genres. By focusing on critical reception of an unlikely group of instrumental chamber works, I elucidate how the acts of performing, listening to, and evaluating "expressionist" music were enmeshed in the complexities of a politicized public concert life in the immediate postwar period. The opening chapters establish broad music-aesthetic and sociopolitical contexts for critics' postwar discussions of "musical expressionism." After the first, introductory chapter, Chapter 2 traces how art and literary critics came to position music as the most expressionist of the arts based on nineteenth-century ideas about the apparently unique ontology of music. Chapter 3 considers how this conception of expressionism led progressive-minded music critics to interpret expressionist music as the next step in the historical development of absolute music. These critics strategically—and controversially—portrayed Schoenberg's "atonal" polyphony as a legitimate …