This document discusses shaft alignment, including basic terms, types of alignment, methods of alignment, and why proper alignment is important. Shaft alignment involves positioning the rotational centers of two shafts to be co-linear. Misalignment can cause increased vibration, energy loss, and loads on bearings and seals. Common types of misalignment are offset and angular. Methods to measure alignment include mechanical methods using straight edges and dial indicators, as well as laser alignment. Proper shaft alignment avoids damage to machines from misalignment forces.