This volume contains most of the contributions presented at the NATO Advanced Research Workshop on Rare Earth Transition Metal Borocarbides (Nitrides): Superconducting, Magnetic and Normal State Properties, held in Dresden, Germany at 13 - 18 June 2000. The Workshop was chaired by K. -H. MUller and V. N. Narozhnyi. This was the first meeting specially focused on the quaternary rare-earth transition-metal borocarbides and nitrides - a new class of magnetic superconductors discovered in 1994. The motivation for organizing this workshop was to bring together scientists (both experimentalists and theoreticians), actively working in this field in different countries, using different methods, to exchange their points of view on the properties ofthese materials and to recognize the directions for future research. Totally 48 participants from 17 countries ofEurope, the United States, BraZil, India, Israel and Japan took part in this meeting. In addition about 15 observers (mainly from Germany) attended. The scientific Programme of the Workshop was composed of 7 sections. The section Introduction and Overview was followed by the Electronic Structure and Properties and Phonon Spectra; Magnetic Properties and CEF Effects; Interplay between Superconductivity and Magnetism; Vortex Lattice; Thin Films; Nature of the Superconducting State in Borocarbides sections. Totally 50 presentations were given (45 ofthem in oral form). Considerable attention was devoted to the characterization of the particular place of borocarbides amongst the other magnetic and superconducting systems and, especially, magnetic superconductors.