Preface. 1. An Introduction to the Formation of Interstitial Alloys through Gas--Solid Reactions; K.H.J. Buschow, G.J. Long, F. Grandjean. 2. Fundamental Concepts and Units in Magnetism and Thermodynamics; F. Grandjean, G.J. Long. 3. Matter and Magnetism: the Origin of the Problem;...