The study of the animal kingdom that comprises of an analysis of the structure, evolution, embryology, classification, habits and distribution of animals is under the scope of animal biology or zoology. It incorporates the disciplines of comparative anatomy, animal physiology, taxonomy, zoography, vertebrate and invertebrate zoology, etc. Animals are classified into distinct groups based on shared characteristics. The branch of science concerned with the identification, description, nomenclature and classification of animals is known as taxonomy. Anatomy deals with the structural organization of all animals. The focus of physiology is to understand how the different structures of the organism such as cells, biomolecules, organs and organ systems execute the various physical and chemical functions essential to the organism. This book provides comprehensive insights into the field of animal biology. It unfolds the innovative aspects of the study of taxonomy, anatomy and physiology, which will be crucial for the progress of this field in the future. It will serve as a valuable source of reference for graduate and post graduate students as well as experts.