Working on teaching as a collective practice--understanding it, specifying it, and improving it--is crucially important and too often ignored. But setting up a choice between improving teaching and improving teachers is problematic for several reasons. To begin with, it seems that the very methods Hiebert and Morris outline for improving teaching necessarily imply the simultaneous improvement of teachers. Improvement as they describe it suggests a "generative dance" between the organizational knowledge embedded in artifacts and the individuals who learn how to use and continuously improve those artifacts. Looking at teaching through the lens of practice theory has two important consequences: it challenges the dichotomy between individual and collective learning, and it focuses attention on the systematization of resources in the organizational setting as an important component of competence building. (Contains 1 note.)