First Published in 2012. The past 150 years have seen dramatic and continuing improvements in health and life expectancy. In the last century alone. Formulating a 21st century public health agenda to address the increasing burden of chronic diseases worldwide will require the same innovation and perseverance. Split into three sections, the first highlights the public health significance of mental health by focusing on the evidence and epidemiology of the burden; the second on policy aspects central to population mental health, including the mental health care system, laws and regulations, and finally the global effort to improve the mental health of populations; focus on public health practice as it applies to mental health care utilization of the population as whole, as well as vulnerable subpopulations, such as children and the elderly.