The temperature on earth varies over a wide range whereas man can only work comfortably in a quite narrow temperature range that has to be artificially maintained. In addition, many industries have extensive requirements for temperature control. Thus control engineers are called upon very frequently to design temperature control loops. A general knowledge of control engineering is of course useful in designing temperature control loops.However, temperature control has some special features: (i) asymmetries caused by the usually differing mechanisms of heating and cooling (ii) complex nonlinear heat-transfer effects (iii) highly application-dependent measurement problems. The intention of this book is to treat the theory and practice of temperature measurement and control, and important related topics such as energy management and air pollution, at a level suitable for engineering and science undergraduate and postgraduate students, and in a manner designed to make the book valuable to practising engineers. There are no specific prerequisites for the book although a knowledge of elementary control theory could be useful. The philosophy of the book is a compromise between fundamentals and practical guidelines. It is the author's firm belief that it is highly desirable to obtain a good insight into theoretical fundamentals (deeper than can be justified on grounds of immediate utility) before embarking on practical applications. The aim has been to produce a practically oriented text within a firm theoretical outline. The first half of the book is an application oriented survey of temperature measurement techniques and devices. The second half is concerned mainly with temperature control in both simple and complex situations. There are chapters on heat sources, commercially available controllers, temperature control in buildings and energy conservation. The book ends with an appendix that rapidly surveys the underpinning thermodynamic theory.