This book provides a unified description of magnetic phenomena through means of the generalized susceptibility. The book begins by discussing the general properties of the susceptibility, its complex nature, its symmetry, and its relation to magnetic fluctuations.Next, the quantum basis of magnetic phenomena is established. The bulk of the book builds on this theoretical foundation to calculate the magnetic response to spatial and time-varying magnetic fields. This provides a natural way of thinking about long-range order, critical phenomena, resonance, etc. A new chapter is included which deals with the magnetic properties of thin film magnetic structures which have many potential applications.

The author has had a long history of research in magnetism. He received his BS from MIT and his PhD from Stanford. He did postdoctoral work with C.Kittel at Berkeley, He was a professor at Stanford where he has had collaborations with T. Geballe and C. Herring. White and Geballe wrote Long Range Order in Solids, a book that treats magnetism and superconductivity as well as other cooperative phenomena from a general point of view. He spent sabbaticals at the Cavendish Laboratory with Sir Neville Mott, the Ecole Polytechnique, and the Max Planck Institute in Stuttgart. Recently he was a professor at Carnegie Mellon University where he was also Director of the Data Storage Systems Center, an interdisciplinary center for magnetic recording. White is also the author of Introduction to Magnetic Recording.

Although it is one of the oldest physical phenomena studied, magnetism con­ tinues to be an active and challenging subject. This is due to the fact that mag­ netic phenomena represent a complex application of quantum mechanics, statistical physics, and electromagnetism. As new magnetic materials are syn­ thesized and new experimental conditions realized, the very fundamentals of these subjects are expanded. Thus, the Kondo effect, like superconductivity, stimulated the development of many-body techniques; spin glasses with their competing interactions are leading to advances in statistical physics; and angle­ and spin-resolved photoemission is probing details of transition-metal electronic states never before possible. I have not tried to incorporate all the new developments in this subject since the first edition ten years ago. My purpose is still the same - to use linear response theory to establish a common conceptual basis for understanding a variety of magnetic phenomena. Many recent developments fit into this frame­ work and have been included.

1. The Magnetic Susceptibility.- 2. The Magnetic Hamiltonian.- 3. The Static Susceptibility of Noninteracting Systems.- 4. The Static Susceptibility of Interacting Systems.- 5. The Dynamic Susceptibility of Weakly Interacting Systems.- 6. The Dynamic Susceptibility of Strongly Interacting Systems.- 7. Magnetic Impurities.- 8. Neutron Scattering.- References.