Pain speaks as forcefully and as personally as any human experience. While the ability to experience pain is essential for survival, chronic pain is the scourge of sentient existence. As a topic of research, pain presents a formidable challenge for scientists. How does individual perception of pain vary? Why are some chronic pains so difficult to control? How effective are alternative and complementary methods, such as acupuncture and hypnosis, and how do they exert their pain-relieving effects?