MIT's 14.01 Principles of Microeconomics opens with Professor Jonathan Gruber framing the whole field in one sentence: individuals and firms trying to make themselves as well off as possible in a world of scarcity. He walks through what that means in practice, introducing constrained optimization as the mathematical backbone of economic decision-making before turning to the course's first real tool, supply and demand. Gruber sketches how buyers and sellers generate market prices, what shifts a demand curve versus a supply curve, and why economists treat these diagrams as more than classroom abstractions. As the opening lecture of MIT's standard microeconomics sequence, it sets vocabulary and method for everything that follows rather than diving into advanced cases. The pace is brisk and lecture-hall plain, aimed at students who have not yet seen an indifference curve or a cost function.