[The articles of this volume will not be reviewed individually.] This volume contains the contributions, both the oral and poster presentations, to the NATO Advanced Research Workshop on “Nonlinear Wave Processes in Biological Media” held at Tetley Hall, University of Leeds, Leeds U.K., September 11-15, 1989. At this meeting 55 researchers from North America and Western Europe, and the Soviet Union and Eastern Europe presented mathematical and experimental results on nonlinear wave phenomena in excitable media and related nonlinear systems through lectures and posters. In spite of their involvement with excitable media for many years many of the participants met here for the first time, and so the main result of the workshop will only appear in the next few years, as these preliminary contacts lead to more extensive collaborations.