Synopsis The science of ecology, born at the beginning of the last century after a gestation period of several hundred years, has now not only matured into an honoured and respected scholarly discipline and field of research but has also become a household word as it relates to the general condition of the environment. This book is an effort to summarize the basic concept and principles of the subject, to present the elementary factual information with which a person to be competent in the field should be familiar, and to show how these principles and facts may be applied in a practical way to the interests and welfare of man. Although the book relates especially to animals, enough material is given concerning plants to bring out their essential place in the system of nature and to emphasize the bioecological point of view.The book has several main themes-first, it is broad in coverage, second main theme is to present both sides of an argument. It is very easy to present an ecological principle with a "happy ending", that is, a nice tidy explanation with no loose ends, that appeals to the student and is intellectually satisfying.The entire information is organised in 18 chapters. Profusely illustrated the book will serve as an ideal text book to the users.