Synopsis Aves constitute a well-defined group of vertebrates. They possess a sense of strongly marked characters such as distinguish hardly any other class. An Introduction to Birds is the second revised edition of the book. This text is designed to approach the morphology, anatomy, physiology and development of the Birds in a coherent way. The book features both a text and a laboratory guide. It deals with the structures and physiological phenomena of each system. Origin, adaptive radiation and other general topics are also dealt in details. It is hoped that this book will not only meet the requirement of Indian students but will also be useful as a guideline to the teachers in their teaching.