Abstract: A wafer handling robot is disclosed for transporting workpieces such as semiconductor wafers and flat panel displays between process tools and/or workpiece storage locations within a wafer fab. The robot includes a base comprising a rigid backbone for providing a significant degree of structural stability to the robot. The base further includes a mast, a linear drive system for translating the mast, and a shoulder drive system for rotating the mast. The shoulder drive system includes a harmonic drive reduction system for providing a stiff, smooth and precise output rotation of the mast section. The robot further includes a proximal link fixedly mounted to the mast for rotation with the mast, and a distal link rotatably mounted to the proximal link. An end effector for supporting various workpieces is rotationally mounted to the distal end of the distal link.