Flir Systems was established in 1978 to pioneer the development of high-performance infrared imaging systems, and is the world leader in the design, manufacture, and marketing of thermal imaging systems for a wide variety of commercial, industrial, and govern­ment applications. Today, Flir Systems embraces several major companies with outstanding achievements in infrared techno­logy since 1958 — e.g., the Swedish Agema Infrared Systems (formerly Aga Infrared Systems), the three United States companies Indigo Systems, FSI, and Inframetrics, and the French company Cedip. In this book, Claes Öhman (ret.)—once the R&D manager at Aga Infrared Systems—introduces the reader to the fundamentals of measurement in thermography.