This textbook is designed for medical students, interns, and clinical residents. It serves as a comprehensive guide for independent, out-of-class study in clinical pharmacology, curated by V.I. Petrov, a leading clinical pharmacologist and senior specialist at the Ministry of Health and Social Development of the Russian Federation, and a corresponding member of the Russian Academy of Medical Sciences. The book systematically presents standards for a clinical pharmacology approach to selecting and prescribing medications for the most common human diseases. In addition to foundational principles, the author offers personal insights into complex issues within clinical pharmacology, grounded in evidence-based medicine. This perspective aims to help novice physicians avoid prescribing errors and to master the effective and safe use of medications. Each chapter includes clinical case analyses that simulate real-world medical practice, enhancing the reader’s understanding and application of the material.