In this chapter, the authors examine developments in the teacher workforce and in the occupation of teaching across recent generations. They take their point of departure from the perspective of prevailing policy discourse on enduring problems of educational equity, asking not only how teaching has evolved in recent decades but more specifically how that evolution has mattered to the distribution of educational opportunity and the shape of educational outcomes. This terrain is arguably large, and the text necessarily reflects certain choices regarding focus and emphasis. Consistent with the overall volume, the authors focus principally on conditions in industrialized nations and on teachers as the object of policies intended to remedy problems of persistent inequity. They acknowledge but do not delve into the extensive and complex body of classroom-based research that locates issues of equity in teachers' pedagogical practices, their relationships with students and families, and the expectations they hold of low-income, minority, or special-needs students. They argue for a policy and research perspective that more fully integrates individual and collective conceptions of teacher quality and that attends more fully to institutional processes and organizational contexts for teaching. (Contains 26 notes.)