Welcome to our course on diagnosing health behaviors for global health programs at the Johns Hopkins Bloomburg School of Public Health. We aim to save lives, millions at a time. But we need to ask ourselves who are these millions of people? What are they doing about their health? And why are they doing those things? We must be aware that in each country and culture, people may be doing different things to make themselves healthy and avoid disease. Or they may be doing similar things, but for very different reasons. Our goal in this course is to provide a learner with some of the basic tools to diagnose behavior in a given context. We also stress that the individual should not be blamed if his or her behavior does not lead to healthy outcomes. We must therefore look at the individual's behavior in a broader ecological context and recognize the influences of peer and social groups, the broader community, the institutions and organizations that provide services. And last but not least, the policy makers who either enable or discourage healthy behavior. Another key lesson is that behavior is not like a light switch that can be turned off and on. We start the course by looking at the dimensions of behavior, at what might make it easy or difficult for a particular behavior to change. For example, in order to prevent Zika or Dengue fevers, which are carried by the Aedes aegypti mosquito, we need to encourage people to cover water containers in their homes. To understand how this behavior might be encouraged, first we need to look at things like frequency, how often does this behavior have to occur? Daily in this case. Then we look at the duration. How often do people need to keep doing this, covering their water containers? Yes, throughout the transmission season of the disease. Then we consider whether the behavior is congruent with the local culture. Will it make sense to people? We also need to understand and ask whether the behavior can be linked with other daily activities to make it easier. So, we must also consider how complex or easy the behavior is to perform. To people need to make special water container covers? Are the covers easy to put on the drums and pots where they collect their water? We will go into more dimensions of the behavior during these lectures. Subsequent lectures will examine other tools and theories that help us understand the factors that influence behavior. The key issue is that having a theory can help us plan better behavior change or reinforcing existing behaviors. These interventions could be better planned for a given setting. We can also use concepts from different theories and devise our own best understanding of how people behave in a given community. We hope that you will find this course complements our other global health offerings on community change, ton raining health workers, and on primary healthcare. Thank you for being part of our course.