[en] This monograph describes the basic physics and chemistry of advanced fuels together with a review of the technological knowledge and possibilities available. The emphasis is put on a critical statement of recommendable data rather than on a complete listing of the extensive literature available. More specifically the basic physical and chemical properties, thermodynamics, fabrication and operating (irradiation) behaviour of carbides and nitrides of U and Pu, as well as of the mixed compounds s(U,Pu)C, (U,Pu)N or (U, Pu)(CN) are described. The full range from basic research to technological application is covered. This includes a description of reprocessing, safety and theoretical modelling of thermal and irradiation behaviour