It is the purpose of this paper to review the recent history of the development of pyrolytic graphite and its thermal, aerothermochemical, and structural properties with regard to its application to hypersonic vehicles. Pyrolytic graphite is not really new since its discovery dates back to Thomas Edison, however, this class of refractory materials has been rediscovered recently because it possesses certain desirable properties at extremely high operating temperatures, including a high strength to weight ratio, low oxidation rate, and a low transverse coefficient of thermal conductivity. Consequently, a thorough investigation of the properties of pyrolytic graphite is being carried out. In addition, theoretical models are being developed so that its aerothermochemical and aerothermostructural behavior can be predicted with confidence for arbitrary hypersonic missions.