Dr. Lee Hood discusses the transition from our current reactive (waiting for illness before visiting a doctor) to proactive, or P4, medicine. P4 medicine is predictive, personalized, preventive and participatory. In 10 years Dr. Hood predicts P4 medicine will dramatically turn the ever escalating costs of medicine around-and indeed rapidly drop the cost of healthcare over the next decade or two to the point it can be exported to the developing world.