Measurement is the process of comparing unknown magnitude of certain parameter with the known predefined standard of that parameter. Measurements are one of vital parts of not only mechanical engineering but all types of engineering fields. Every branch of engineering comprises two processes: design, and operations and maintenance. The design may be machine design, building design, circuit design, transportation design, and automobile design etc. The operations part includes operation of the machines, automobiles, various plants, circuits etc. Both, the design, and operations and maintenance involve measurements. For instance while designing automobile we have to consider dimensions of various parts of the automobiles, the loads they can pick up etc. Likewise during the operations of the plant, say like industrial refrigeration plant, we have to measure parameters like pressure, temperature, etc. In the power plant we have to measure various quantities of the coal, the quantity of water in the boiler, the amount of steam produced along with its flow rate, temperature and pressure, the amount of power produced, the outlet temperature of the steam from condenser etc. In the large chemical plants large numbers of such parameters have to be measured. Theory and Design for Mechanical Measurements provides a timely and in–depth reference to the theory of engineering measurements, measurement system performance, and instrumentation.