Economic agents often act in face of uncertain conditions. An individual, for example, can only assess the probability of a loss when deciding to purchase an insurance policy. Similarly, a firm does not know the productivity of potential employees; and, to keep the list short, an auctioneer usually does not know how much bidders value the object for sale. Despite the intrinsic uncertainty, the above (as well as related) problems are amenable to economic analysis and in this course we will learn the tools that make that analysis possible. The careful application of these tools will help students build important analytical skills, frequently demanded from modern economists.