A general approach for developing a "global" crossover EOS, which in the critical region reproduces theoretically well-established scaling laws, and in the limit of low densities is transformed into the ideal gas equation is described. Using a simple cubic EOS as a reference EOS for one-component fluids, a generalized corresponding sstate model for pure fluids and fluid mixtures, which in addition to the accentric factor ? contains also the Ginzburg Gi as a parameter is developed.