Evolution is a natural process that drives a change in the heritable characteristics of populations over successive generations. Such changes are mediated by genes as they are transmitted from one parent to offspring. Evolution is at the core of the emergence of biodiversity at each stage of biological organization such as at species, organisms and molecular levels. Genetic variations in a population are introduced due to mutations and genetic recombination. Some of these characteristics become common or rare within a specific population due to evolutionary processes of natural selection and genetic drift. The impact of evolution is seen in terms of change in adaptability, cooperation among species, coevolution, speciation and extinction. This book is a valuable compilation of topics, ranging from the basic to the most complex theories and principles in the field of evolution. The topics included herein are of the utmost significance and bound to provide incredible insights to readers. This textbook is an essential guide for both academicians and those who wish to pursue this discipline further.