Overview: The constructive role of noise in fluctuation driven transport and stochastic resonance.

Random noise is typically thought of as the enemy of order rather than as a constructive influence. Recent work has shown however that under certain circumstances, noise and Brownian motion can facilitate transmission of information via a mechanism know as stochastic resonance, and help systems use chemical energy and nonequilibrium fluctuations to drive directed motion via fluctuation driven transport. In this focus issue we have collected several articles that capture the flavor of these developing fields and point the way to new directions for research. (c) 1998 American Institute of Physics.