Explores narratives about teacher work articulated through representations of substitute teachers, using this representation to render visible assumptions governing boundaries of professionalism. The article discusses professional teachers as constructed in educational reform; images of substitute teachers (incompetent, unqualified, deviant outsider, and guerilla superhero) proliferating in popular culture and educational practitioner discourses; and how other teachers function in the context of teacher shortage, educational reform, and school practice. (SM)