This paper briefly examines theories of affect and some of its possibilities and limits for mathematics education research. First, psychological, socio-cultural, embodied, and new materialist perspectives are considered. The paper juxtaposes emerging and older theories of affect in mathematics education with alternative approaches in the humanities and social sciences. Then, the paper briefly historicizes some of the changing and enduring economies for affect in mathematics education across three historicized "moments" of U.S. mathematics education reform circa the 1830s, 1890s, and 1930s. This section aims to consider some of the ways 'bodies' have become differently legible for theorizing affect in problematic ways with potential implications for future research. [For the complete proceedings, see ED629884.]