implementation of the chaotic cosmology program. Misner (1968) was the first to try out this program in a Bianchi type-I universe with the neutrino viscosity at work in the lepton era. Though this specific process was found to be too weak to damp away the shear, the idea remains a very attractive one. As we will see, it can indeed be accomplished with a more powerful process, that of vacuum particle production at the Planck time. The philosophy of chaotic cosmology is similar to that behind the inflationary cosmology of Guth (1981), where the initial conditions are rendered insignificant by the evolutionary process, which, in this case is inflation.

Second, the chaotic cosmology program ushered in serious studies of the dynamics of Bianchi universes. This was exemplified by Misner’s elegant work on the mixmaster universe (1969a). (That was when one of us first entered the scene.) The ingeneous use of pictorial representation of the curvature potentials made the complicated dynamics of these models easy to follow and opened the way to a systematic analaysis of this important class of cosmology. (See Ryan and Shepley 1975.) This development complements and furthers the ongoing program of Lifshitz, Khalatnikov and Belinsky (1963, 1970) 