We can change these trends. Baltimore, a city that has had a series of activist and ambitious health commissioners in recent years, still lags the national averages in life expectancy, but it is catching up, thanks in large part to a focus on reducing infant mortality and violence and the adoption of policies designed to reduce health disparities. The city has a long way to go, but it is under no illusions about that fact and it is making aggressive efforts to enlist community groups, businesses, hospitals, churches and every other segment of society in the effort.