Decision making is a process in which we select a course of action among available options. It begins when we need to do something but we do not know what. First, we embark on a journey into a land of rationality to study the normative approach. Since our ability to think and knowledge are limited and time is pressing, it is not surprising that some behavioral biases will observed in decision making processes. Of course, this will require adjusting our normative theories to capture these biases. This will be the second purpose of this course.