This book is a humble contribution to the health teams in the Americas providing them with the experience and lessons learned during the twenty years of application of the new primary health care model in Chile. It represents a lifetime pursue of a new model of a health care, not only a more efficient model, but most importantly humane and protective of the family health and the environment. This health care model can evidence that a solid health care can also help society procure its development and economic growth, thus establishing that health care is not a expenditure but an investment. Furthermore, this book celebrates the 40th anniversary of the Sophie Davies School of Biomedical Education of CCNY of NYC, pioneer in educating primary care physicians. As one of its founders, I wish to share my experience with all the graduates of the School. The purpose of this book is to establish the fundamental principles that should be taken into consideration when setting up a health system for a society. Those principles should not only respond to the actual mortality, morbidity and environmental challenges of the population, but also it should establish the measures to prevent diseases and environmental damages. The most prevalent health problems affecting societies today cannot be "cured" they can only be prevented. This is the reason why it has became imparative to change the actual health care systems to a health care system that protects the person, the family and the environment. The challenges fase by humanity at this point in time need to be resolved in order to avert a catastrophic end. As health professionals we need to understand that our role in society is to provide effective health care that responds to all the variables that affect the health of the individual and the environment. This book can contribute to our quest to search for a better health care system in the Americas.