Asymptotic and exact solutions of perfect-fluid scalar-tensor cosmologies

We present a method which enables exact solutions to be found for flat homogeneous and isotropic scalar-tensor cosmologies with an arbitrary omega(Phi) function, and satisfying the general perfect fluid state equation P =(gamma - 1)rho c(2). This method has been used to analyze a wide range of asymptotic analytical solutions at early and late times for different epochs in cosmic history: false vacuum inflationary models, vacuum and radiation-dominated models, and matter-dominated models. We also describe the qualitative behavior of models at intermediary times and give exact solutions at any time for some particular scalar-tensor theories. [S0556-2821(99)02412-1].