The history of pharmacology travels along with that of scientific methodologies and the novel frontiers of pharmacology give way to a novel world in search of drugs and advanced technologies. Constant growth in this field has also altered significantly the way of designing a fresh drug. Modern drug discovery is actually based on profound knowledge regarding the disease and both molecular as well as cellular mechanisms involved in its development. The aim of this book is to provide valuable information regarding the field of pharmacology, starting from pharmacodynamics, with an experimental study and extending up to the latest field of pharmacogenetic.