Book excerpt: This book is based on the contributions to a course, entitled Applied Magnetism, which was the 25th Course of the International School of Materials Science and Technology. The Course was held as a NATO Advanced Study Institute at the Ettore Majorana Centre in Erice, Sicily, Italy between the 1st and 12th July 1992, and attracted almost 70 participants from 15 different countries. The book deals with the theory, experiments and applications of the main topical areas of applied magnetism. These selected areas include the physics of magnetic recording, magnetic and magneto-optic recording devices, systems and media, magnetic fine particles, magnetic separation, domains and domain walls in soft magnetic materials, permanent magnets, magnetoresistance, thin film magneto-optics, and finally, microwave, optical and computational magnetics. The material is organised into I 0 self-contained chapters which together provide a comprehensive coverage of the subject of applied magnetism. The aim is to emphasise the connection between the fundamental theoretical concepts, key experiments and the important technological developments which have been achieved in this field up to the present time. Moreover, when and where possible, pointers to future trends are indicated which hopefully, together with the background material, will promote further advancement of research. The organizing committee would like to acknowledge the sponsorship of the NATO Scientific Affairs Division, the National Science Foundation of the USA, the Science and Engineering Research Council of the UK, the Italian Ministry of Education, the Italian Ministry of University and Scientific Research and the Sicilian Regional Government.