Post-traumatic stress disorder (PTSD) haunts some 300,000 veterans who have returned from Afghanistan or Iraq. Drugs and psychotherapy provide only partial relief. Increasingly, vets are turning to other techniques, including meditation, yoga and breathwork, to heal their trauma, sense of isolation, and anger, and to reclaim their lives. Researchers have shown that Sudarshan Kriya Yoga, or SKY, a week-long breathing exercise program, has a long-lasting impact on anxiety and PTSD. How does science explain the link between a focus on the breath and reduced stress? Are these techniques useful for healing other forms of trauma? Introduction by Jerry Greenwald