Written primarily for students of medicine, pharmacy, and pharmacology, this introductory book provides a concise summary of the principles that underlie the science of pharmacology. It presents the basic concepts required for understanding the use, mechanisms of action, toxicity and side effects, and therapeutic application of drugs in man. Thus the book may also be of interest to medical practitioners and to biological and medical scientists. Among topics covered are the sources of drugs, the way they are administered and dealt with in the body, as well as concepts about the nature of their actions. The last include their chemical interactions with components of cells and the manner in which these lead to therapeutically desirable as well as undesirable and even toxic effects. In addition, clinically related subjects, such as drug interactions, teratogenic and carcigenic effects are discussed. The development and testing of new drugs are also described. For easy reference, at the back of the book there is a glossary of drugs named in the text.