The universe is a large island of mass and energy. This book gives solid theoretical and experimental reasons to believe that there is more beyond the boundaries of the universe: a Megaverse containing many island universes, of which our universe is one. It then characterizes the features of universes and the Megaverse. In particular it points out that each universe lies in a high dimension Megaverse, which appears to be sixty-four dimensional, based on an extrapolation of features of our universe. Due to the high dimensionality of the Megaverse every point of our universe is surrounded by exterior Megaverse points. The barrier that prevents us from entering the Megaverse is a type of surface tension force - that is infinite for a flat universe such as ours. Thus everything in our universe is confined to it. The book develops the equations for the surface tension force between a universe and the Megaverse. It shows that it is possible for a 'starship' to penetrate the 'veil' of a universe and enter the Megaverse using a large gravitational field (perhaps around a neutron star) to create a curvature 'bubble' and a high starship velocity simulating a high temperature (the Eotvos effect). Together the confining force can be reduced to zero allowing a starship to enter the Megaverse.

The book covers many additional topics: interactions between universes, particle theory in the Megaverse between universes, the Big Bang and the expansion of our universe, a steady state model of the universe based on infalling mass-energy from the Megaverse, the impact of universe surface tension on the expansion of our universe, leaky universes that exchange mass-energy with the Megaverse, the quantum field theory of universes and the Megaverse, the possibility of Megaversian life, and so on.

The WheelerDeWitt equation furnishes us the framework for a quantum Megaverse containing quantum universes. With it we can define a universe particle theory rather like elementary particle theory with interacting universes, and universe-antiuniverse creation from vacuum fluctuations.

The latter part of the book discusses why the Megaverse is likely to be of great interest and why we should go there. We describe starship designs including a design to escape the universe with a slingshot maneuver around a neutron star taking advantage of surface tension force reduction techniques. Aspects of starship communications and life support are also discussed. The author believes that Mankind must eventually go beyond the stars into the other universes of the Megaverse.