One of the dominant themes in the history of physics in this century has been the effort to understand condensed states of matter. This began with very simple systems — the Van der Waals description of the liquid–gas transition and the Weiss mean field theory of ferromagnetism — and has gradually developed to include more and more complex and subtle states and phenomena. Spin glasses are the current frontier in this development, the most complex kind of condensed state encountered so far in solid state physics.

In trying to understand these systems, experimentalists have used a wide spectrum of probes in ingenious ways, and theorists have invented an equally wide variety of models and new theoretical concepts. The resulting developments have had an impact, not only on other parts of physics, but also on other fields such as computer science, mathematics, and biology. It is because of this widespread influence and the interest in spin glasses that it has aroused that we are writing this book.

We expect that many people who read this book will be condensed matter physicists. However, we also have in mind as a typical reader someone from another area in physics, or perhaps a graduate student looking for a research topic, who wants to find out what all the excitement is about.