The Maxwell relaxation theory leading to the concept of a viscous‐elastic body is briefly stated. Extensions to systems built up from several such viscous‐elastic components with different relaxation times are discussed. In the case of high molecular weight materials, it is more appropriate to assume a continuous distribution of relaxation rates. Equations are formulated whose solution gives the distribution function in terms of the rate of deformation and of the applied stress or the elongation in terms of the two other quantities. The connection with the corresponding distribution of dielectric relaxation times, molecular inhomogeneity and chain branching, and effects at mechanical frequencies large compared with the relaxation rates, are pointed out.