In many applications that include rotating or translating objects, severe vibrations can occur. Such applications include vehicle wheels, internal combustion engines, reciprocating compressors, fans, electric motors, and steam and gas turbines. At high speeds, or speeds that are close to the natural frequencies of vibrations of a machine, significant levels of vibrations can be experienced. You just need to remember the last time that you drove a car in which the wheels were not properly balanced! Severe vibrations can also result in noise, cyclic loading, and structural fatigue. In order to prevent such problems, we should keep vibrations at an acceptable level by balancing. Chapter 14 covers the static and dynamic balancing of short and long rotors. These are important topics and find applications in rotating machinery and especially at high speeds. This chapter also includes discussions on calculating shaking forces in machines that have reciprocating members like internal combustion engines and reciprocating compressors.