Evolutionary Biology is a fast developing subject to encompass animals and plants, past and present. This book on Organic Evolution is an updated exposition of the subject to include the latest concepts, theories and observations in a simple and lucid language. Text is divided into five parts: Part-I deals with concepts, evidences and theories of evolution. Part-II peeps into the Mechanism of Evolution. Part-Ill provides a systematic approach to the process of Speciation. Part-IV explores the basic patterns of Evolution, and Part-V provides an insight into the origin of life, fossil-records and history of life on Earth. Text is profusely illustrated with diagrams to ensure an easy comprehension of the underlying concepts. The book would be a useful textbook for students of biological sciences.