Have you ever wondered why the price of a carton of milk stays about the same week after week, even though thousands of dairy farms are out there? Or why a small wheat farmer can’t just raise his own price above the market price? This chapter explains the logic of perfect competition — a market structure where many small firms produce identical goods and no single player can influence the price. We’ll see how these “price-taking” firms decide how much to produce, when to stay open or shut down, and how the market settles into a long-run balance that benefits buyers.