Over the last two years, I have written a few times about the work that the team and I have been doing on discovering the secret of Bangladesh’s ability to produce so much improvement in the health status of the people. The project was created to mark the 25th anniversary of the original publication of Good Health at Low Cost, and with support from the Rockefeller Foundation, a team of researchers at the London School of Hygiene and Tropical Medicine, along with partner institutions from Bangladesh, Tamil Nadu, Ethiopia, Kyrgyzstan, and Thailand, revisited the original messages. We asked: Why do some developing countries manage to achieve advances in health while others falter? What factors drive improvements in the health system and in access to primary health care? How can we act on the social determinants of health in cash-strapped economies? How have the study countries achieved the health status we observe today? While many determinants of health remain unchanged, Good Health at Low Cost 2011 highlights the greater potential of health systems to improve health.