From the view of antitrust, we want to estimate market power. (For example, the regulator wants to know whether a proposed merger should be allowed.) Since products in most industries are horizontally diferentiated, we will spend most of the time on consumer’s discrete choice of products in a diferentiated market. We will introduce the BLP’s (Berry, Levinsohn, and Pakes) framework to empirically analyze this discrete choice problem. We then apply this framework to study various issues, such as price discrimination, competition of durable products, environmental policies. We will also teach Matlab programming to apply these empirical methods.