Theory of Highway Traffic Signals, Gordon F. Newell, Institute of Transportation Studies, University of California, Berkeley, 1989, 442 pp—reviewed by Vanolin F. Hurdle. Operational Research '90, edited by Hugh E. Bradley, Pergamon Press, New York, 1991—reviewed by Arjang A. Assad. Simulated Annealing and Boltzmann Machines, Emile Aarts and Jan Korst, Wiley-Interscience Series in Discrete Mathematics and Optimization, New York, 1988—reviewed by Olivier Goldschmidt.