In order to facilitate a better understanding of the "how's" and "why's" behind current drug therapies administered in the veterinary field, this text takes a comprehensive look at therapeutic agents in use today. Following a unique body systems organization method, this text clearly identifies and rationalizes the effects of veterinary medication treatments that will allow better anticipation of a patient's response to various remedies. A variety of review methods including self-tests, summary tables, and critical thinking questions aid the reader's understanding of material presented and allow for practical application in the veterinary world.