Book excerpt: The concept of temperature. The thermodynamic temperature scale. Entropy, temperature and statistical mechanics. The international practical temperature scale. General characteristics of temperature measuring devices and treatment of data. Liquid-in-glass thermometers. Sealed liquid or gas sensing instruments and bimetallic sensors. Electrical resistance temperature measurement using metallic sensors. Thermistors and semiconductors for temperature measurement. Thermoelectric temperature measurement. Theory of radiant heat transfer as a basis for temperature measurement bu radiant techniques. The disappearing filament optical pyrometer. Photoelectric optical pyrometers (automatic and infrared). Total radiation pyrometers. Novel methods of temperature measurement. Pyrometric cones. Calibration methods. Installation effects. Dynamic response of sensors. Temperature instrumentation and control. Thermocouple reference tables.