A comprehensive and general method for the prediction of strong motion amplitudes, developed by Strong Motion Research Group at University of Southern California, is reviewed. It uses synthetic translational accelerograms and the theory of linear wave propagation to predict all other components of strong motion: rotations (torsion and rocking), strains and curvatures. It gives site-specific synthetic motions which have realistic non-stationary frequency content, site-specific dispersion properties, and amplitudes and the duration which are compatible with empirical scaling equations developed for the estimation of strong motion in California.