Acupuncture is widely practised in the 21st century in scientifically developed countries for a wide range of ailments, ranging from chronic pain, giddiness and high blood pressure to gastrointestinal disorders and sexual dysfunction. Yet the reasons for its vaunted effectiveness remain a matter of controversy. In ancient China, its mechanism of action was understood in abstract terms, promoting the flow of qi and the balance of yin and yang through the body's meridians - a complex network painstakingly charted but never found. Modern medical researchers have examined old and new needling points, viewing them as "trigger points" that stimulate physiological responses in the body. There is also mounting evidence of strong placebo effects. This volume contains twelve articles covering the latest research on the scientific explanations of the mechanism of acupuncture and critical reviews of clinical trials on its efficacy by leading scholars, including Edzard Ernst of Exeter, Thomas Lundeberg of Karolinska Institute, Lixing Lao of the University of Maryland and Ping-Chung Leung at the Chinese University of Hong Kong.