Pharmacology explores how drugs interact with the body and how the body alters drugs—knowledge essential for safe and effective treatment. Understanding drug mechanisms, indications, side effects, and interactions underpins every prescribing decision. This compact text distils core pharmacological principles into concise, clinically oriented chapters organized by drug class and therapeutic use. Emphasis is placed on dose rationale, common adverse effects, and practical prescribing considerations for different patient groups. Useful summaries, dosing tables, and mnemonics support rapid review for students and healthcare professionals. The book is written to help readers move from memorization toward safe, rational drug use in clinical practice.