This survey of the principles and applications of temperature control in industrial processes is supported by the National Bureau of Standards. It describes the fundamentals of thermometrics, construction and accuracy of modern thermometric devices, use of microprocessors and larger computers for automatic process control, and how to interpret readings. Essential background information is covered together with calibration techniques and applications in industries such as primary metals, steel, aluminum, glass, and plastics. Also included are infrared imaging techniques for estimating heat losses from buildings and equipment.