Modern flute pedagogy tends to focus on repertoire which utilizes or builds upon tonal and Romantic stylistic conventions, largely ignoring works that disregard or reject these conventions until later in student's education. This lack of stylistic diversity in commonly studied works from the first half of the twentieth century can be problematic when students are approaching avant-garde or modernist repertoire for the first time, as they are unfamiliar with the style and technical needs of the pieces. This dissertation provides a style guide and progressive curriculum for the avant-garde repertoire of the early- and mid-twentieth century to help students bridge the gap from commonly-studied early-twentieth century repertoire to Post-War Modernist works. The curriculum and style guide are accompanied by an overview of avant-garde musical styles prominent in Europe and American between the 1890s and 1970s, a discussion of the pedagogical challenges of avant-garde repertoire, and two performance guides for avant-garde pieces included in the curriculum, Diaphonic Suite No. 1 by Ruth Crawford and Variations for Solo Flute by Ursula Mamlok.