The classical approach in regional and urban modeling is static. Actual models are taking into account the interactions between economic regions only in their spatiality. However, economic regions and urban agglomerations are evolving in time. Urban population grows continuously in time and expands the areal of living. It also is trivial that population tend to displace from one region to another. Under these circumstance a reconstruction of Regional and Urban Economics, based on their time evolution was imperative. The three papers reunited in this book converge in a new and unitary image of economics at regional and urban level. Three new economic phenomenons are discussed in this book. The population grow in urban areas modeled according to a new found equation emerges in the phenomenon of cities”collision”. The second chapter of the book deals with population movement between economic regions, a movement that is found to evolve according to a wave equation, namely Gravitational Wave Equation. Why populations tend to agglomerate in restricted regions in space? The answer can be found in the last chapter of the book.