Written in the award-winning Incredibly Easy! style, this book provides complete and clear explanations of how drugs act and interact in the treatment of disease. Focusing on mechanisms of drug action, the book details specific drugs by pharmacologic class for all body systems as well as drugs for pain, psychiatric disorders, infection, fluid and electrolyte imbalances, and cancer. Potentially dangerous drug and drug-herb interactions are highlighted. This thoroughly updated edition covers the newest drugs in each pharmacologic class and includes information on obesity drugs, a new chapter on genitourinary system drugs, a new medication safety feature, and a new appendix on common herbal preparations and their drug interactions.