This chapter provides information on types of scan mirrors, fabrication techniques to create these mirrors, and typical specifications for these mirrors. The types are prismatic polygonal, pyramidal polygonal, "monogons" and irregular polygonal scanning mirrors. Material selection for polygonal mirrors is driven by considerations of performance and cost. The polygonal mirror requires a bearing system and a drive mechanism to turn it into a functional scanner. Drive mechanisms include pneumatic, AC hysteresis synchronous, and brushless DC. Bearing systems used in most applications are ball bearing, aerostatic air bearings, or aerodynamic air bearings. The chapter includes a section on properly specifying a polygonal scanner as well as the cost drivers in the scanner design. It reviews the incorporation of the scanner into a scan system including system level specifications and design approaches. The chapter also covers system image defects and methods used to compensate for these defects in a scanning system.