According to American Pain Society estimates, 50 million people are partially or totally disabled by pain and 45% of all Americans seek care for persistent pain at some point in their lives. Pain is one of the most common reasons patients seek medical attention and a symptom encountered by every physician. it addresses principles of pain physiology, pain assessment, pharmacologic and nonpharmacologic management options, pain in special populations (e.g., older adults, children), persistent nonmalignant pain, and cancer pain.