A Synergetic Approach to Problems of Nonlinear Dispersive Wave Propagation and Interaction††This paper is dedicated to Professor L. Biermann on his sixtieth birthday. I would like to express my gratitude to Professor Biermann and his Institute of Astrophysics of the Max-Planck-Institute for Physics and Astrophysics for the support they gave to the International School of Nonlinear Mathematics and Physics held in Munich during the summer of 1966.