Part II — How Markets Work: Microeconomic Foundations
The price system is one of the most remarkable institutions human beings have ever produced — and understanding how it works is the central task of microeconomics.
Markets coordinate the decisions of billions of people every day with no central planner. Nobody schedules the world's wheat harvest. Nobody assigns workers to coffee shops. Nobody determines that there will be exactly enough laptops produced this year to match demand from buyers nobody has met. And yet — most of the time, in most places, for most goods — the system works. People who want laptops can buy them. People who can produce laptops can find buyers. The price adjusts until quantity supplied roughly matches quantity demanded. This is so ordinary we forget how strange it is.
The six chapters in Part II teach you the model that makes this coordination legible: supply and demand. By the end of the part, you should be able to analyze any market — housing in Millbrook, oil in the global economy, labor in your local restaurant industry, beans in a Brazilian supermarket — using the same toolkit. You should be able to predict how prices and quantities respond when conditions change, evaluate the consequences of common government interventions, and recognize the situations where the standard model breaks down because real human beings don't behave the way the model assumes.
Chapter 5 — Supply and Demand is the foundational chapter of the entire book. Everything that follows builds on it. Take your time. The chapter constructs the supply-and-demand model from intuition (why demand slopes down; why supply slopes up), introduces the concept of equilibrium, and walks through the five things that shift each curve. By the end of the chapter, you should be able to look at a real market — say, Millbrook's housing market in 2024 — and figure out which curve shifted and why.
Chapter 6 — Elasticity introduces the most useful number in microeconomics. Elasticity tells you how much quantity responds to price. The chapter walks through how to calculate it, what makes a good elastic and what makes a good inelastic, and what elasticity tells you about who bears the burden of a tax. The minimum wage debate threads through this chapter as a running example.
Chapter 7 — Government Intervention is where price ceilings (rent control) and price floors (minimum wage) get treated honestly — both as the standard supply-and-demand model predicts they will work and as the empirical evidence (especially Card and Krueger on minimum wage) has complicated those predictions. The chapter is the first place in the book where the tone of "here's what economists on both sides argue, here's the evidence each side cites, and here's where consensus exists" becomes a sustained pattern.
Chapter 8 — Consumer and Producer Surplus turns the supply-and-demand diagram into a tool for measuring who gains how much from a market — and who loses how much from a tax, a subsidy, or a price control. The chapter introduces the efficiency-equity tradeoff, the central tension that runs through the whole rest of the book.
Chapter 9 — International Trade scales comparative advantage up to countries and shows how tariffs work on a supply-and-demand diagram. The chapter is honest about both economists' general support for free trade and the real distributional damage that trade with low-wage countries (especially the "China shock") has caused in some communities.
Chapter 10 — Behavioral Economics is a full chapter, not a sidebar. By the end of this chapter, you have a behavioral lens — and the rest of the book asks you to use it.
When you finish Part II, you have the analytical core of microeconomics. The next part will show you when that core is not enough.