For several years there has been increasing demand for self-contained, light-weight electrical and hydraulic power systems for various missile and other aerospace vehicle applications. This Aerospace Information Report intends to discuss one particular category known as Cryogenically Fueled Dynamic Power Systems. In this report, "Cryogenically Fueled Dynamic Power Systems" include all open cycle, chemically fueled, dynamic engine power systems which utilize cryogenic fuels and oxidizers. For nearly all practical present day systems, this category is limited to cryogenic hydrogen or hydrogen-oxygen fueled cycles with potential in future, more advanced systems for replacement of oxygen by fluorine. Excluded from the category are static cryogenic systems (e.g., fuel cells) and chemical dynamic power systems which utilize earth storable propellants.