Optical instruments are routinely employed to obtain a wealth of information about the atmosphere, including its composition, temperature, and winds. A bewildering variety of optical instruments have been proposed over the years, making it difficult to decide which instrument should be chosen to make a specific measurement. Spectral Imaging of the Atmosphere traces the historical development of both spectral and imaging methods and places them in a unified framework relevant to observations of the troposphere, stratosphere, mesosphere and thermosphere. The underlying concepts of various