Theories of form in tonal music have largely been predicated on thematic and/or harmonic criteria. By contrast, this essay supports Edward T. Cone's argument that the essence of tonal form is, by and large, rhythmic. By integrating concepts derived from James Hepokoski and Warren Darcy's Sonata Theory on the one hand, and analytical tools developed by William Rothstein and David Temperley on the other, this article demonstrates that phrase rhythm can construct stylistic norms, establish sonata types, differentiate between levels of compositional choice, and create deformations through the expansion or even rejection of normative procedures. Thus the interaction of rhythm, meter, and hypermeter within phrase structure proves to be a primary factor in understanding tonal form.