The development of the molecular theory of configurational relaxation phenomena in polymers is briefly reviewed with the emphasis on the method of generalized diffusion equation and Rouse's model.Various dispersion phenomena in polymeric systems such as of dynamic viscosity, of dynamic Young's modulus and of dynamic bulk modulus are elucidated on the basis of the model theory. The present theoretical situation of the dispersion phenomena in crystalline polymers is also discussed. at University of Pennsylvania Library on April 12, 2015 http://ptps.oxfordjournals.org/ Downloaded from * More precisely [71] = kM(Y, (0.5