The problems of modern society are complex, interdisciplinary and nonlin­ ear. ~onlinear problems are therefore abundant in several diverse disciplines. Since explicit analytic solutions of nonlinear problems in terms of familiar, well­ trained functions of analysis are rarely possible, one needs to exploit various approximate methods. There do exist a number of powerful procedures for ob­ taining approximate solutions of nonlinear problems such as, Newton- Raphson method, Galerkins method, expansion methods, dynamic programming, itera­ tive techniques, truncation methods, method of upper and lower bounds and Chapligin method, to name a few. Let us turn to the fruitful idea of Chapligin, see [27] (vol I), for obtaining