Since the introduction of the jet engine and its increasing refinement, fuel began to assume a much more prominent role in the overall design of the aircraft [1-1]. Fuel has now reached at least an equal design consideration as the engine and airframe [1-2]. There are several reasons for this increased importance of the fuel in the overall system. In addition to its essential function of providing the energy necessary for flight [1-3], the fuel will act as the primary heat sink required for cooling the aircraft and its equipment [1-4]. In many future systems, the fuel will constitute over fifty percent (50%) of the total weight [1-5] of the system and the fuel cost may well be as high as fifty percent (50%) of the direct operating cost (Figure. 1.1.). The purpose of this mini book is to summarize the progress made to date in the development of these advanced hydrocarbon fuels and to submit the necessary requirements for future hydrocarbon fuels for the aerospace industry. The idea of regular supersonic flight of air-breathing weapon systems has become a reality within previous years and the advancement of even faster systems will continue [1-7]. This incredible boost in flight speed has led to significant increases in the relative value of the fuel to the general system [1-8]. In the period of the piston engine, airplane designers were more concerned with the engine and the airframe rather than with the fuel [1-9]. The choice of fuel to be utilized in the airplane was often of secondary significance [1-9]. All things considered, with the presentation of the jet engine motor and its expanding change, the fuel began to assume significantly more fundamental capacity in the general plan till the point has now achieved where the fuel has obtained at least proportionate status with the motor and the airframe [1-10].