An introduction to the subject of plume phenomenology as it relates to the development of space-based defense systems. Covers the elementary principles of a number of propellant related disciplines including combustion, gas dynamics of supersonic exhaust plumes, infrared radiation processes, theoretical plume models, physical properties of exhaust constituents, diagnostic measurement techniques, and other related topics. Written at a level that is meant to bridge the gap between the needs of space systems engineers and the scientists they work with that are involved with plume observables.