Spin glasses are a fascinating new topic in condensed matter physics which developed essentially after the middle of the 1970's. The aim of this book is to give an introduction to it which will both attract the newcomer to the field (say, a student with a basic knowledge of solid state physics and statistical mechanics) and give a comprehensive survey to the expert who perhaps has worked on a very specific problem. It is a field which is still open to new ideas and concepts and in which important new experiments can certainly still be done.

Our understanding of spin glasses is based on three approaches: theory, experiment, and computer simulation. We have tried to present the most important developments in all of them. One possibility is to take the theory as a guide and to check it by comparison with experimental data and simulations. This is roughly what we do in the first part of this book (Chapters 3 to 6), after introducing the basic experiments, models and concepts which define what we are talking about. (Spin glasses are disordered systems, so we have to introduce several concepts which are unknown in the ‘classical’ theory of ideal solids.)

In Chapters 3 to 6 we discuss a mean field theory, which is so far the only well-established spin glass theory. It turns out to be highly nontrivial and has been developed over more than a decade.