Most physicists, most of the time, are engaged in what Thomas Kuhn calls “normal science,” the process of solving problems under a prevailing paradigm. Part of Edwin Jaynes' career has been profitably devoted to this enterprise, but his best known work may aptly be called “abnormal” in this sense. We organized the Symposium on Physics and Probability not only to recognize Jaynes' accomplishments, but also to celebrate the scientific style and integrity that have been an inspiration to so many of his students and colleagues.

The articles in this volume are based, with a few exceptions, on lectures given at the Symposium, which was held 15-16 May 1992 at the University of Wyoming. The occasion for the Symposium was Jaynes' official retirement from his position as Wayman Crow Professor of Physics at Washington University — as well as to commemorate his seventieth birthday. The authors are former graduate students of Professor Jaynes, or colleagues, or people whose work has been so directly influenced by Jaynes that it was deemed appropriate to invite them to speak at the Symposium.

Jaynes is best known for his work in statistical physics and quantum optics. His seminal papers on information theory and statistical mechanics formulated the latter (in the spirit of Gibbs) without an ergodic hypothesis, relying instead on the maximum entropy principle to assign probabilities in a manner least biased with respect to the available information.