This is a two consecutive semesters course. There are five major parts of subjects to be introduced in this course. The subjects of the first part are about the household. We will focus on individual consumer's decision making with and without uncertainty. In the second part, we will focus on the decision making at the level of individual firm. Given the technological opportunities available to it, how much output will a firm choose to see, and how will the firm go about producing this output? In the third part, the competitive model will be introduced. We will see a competitive market produces results that are in some sense "good". In the fourth, we will see different kinds of market structures. The price and output decisions under different market structrue will be analyzed and compared with those under perfect competition. In the last part, the problem of missing market will be discussed. In the presence of asymmetric information, the markets for certain commodities may not come into existence. Even if markets exist, they may fail to allocate resources efficiently. 《keywords：個體經濟學一Microeconomics I, ☑️消費者行為Consumer behavior, ☑️比較靜態與需求函數Comparative static demand function, ☑️ 需求與供給demand and supply, ☑️無異曲線indifference curve, ☑️市場均衡market equilibrium, ☑️效用函數utility function, ☑️彈性elasticity , ☑️供給行為Supply Behavior》