In evolution, natural selection is the gradual, non-random, process by which biological traits become either more or less common in a population as a function of differential reproduction of their bearers. In this book, the authors present current research in the biological processes, theory and role in evolution of natural selection. Topics include evolutionary transitions in mathematical modelling complexity using evolutionary systemic modelling; natural selection applications for algorithmic computation; allozymes, and DNA and natural selection in the mollusc population.