Part One is the analytic opening of Capital, and it is the part Marx himself flags as the hardest and the most consequential. Three chapters take the commodity apart down to its cell and rebuild the whole apparatus of value, exchange, and money out of what is found inside it. Nothing in the rest of the volume — labour-power, surplus-value, the working day, accumulation — can be stated until the categories built here are standing. Chapter 1 dissects the commodity into use-value and value, tracks value back to the double character of the labour that produces it, derives the value-form through four stages up to the money-form, and then, in the fetishism section, explains why this whole structure presents itself to the people living inside it as a property of things rather than a relation between them. Chapter 2 stages the derivation a second time from the side of the commodity-owners, as an act they perform without grasping. Chapter 3 unfolds money into its functions: measure of value, means of circulation, and money as money — hoard, means of payment, world money.

The situation the Part enters is the critique of political economy. Classical political economy had already found that the magnitude of a commodity's value is governed by labour-time. What it had never asked is why the product of labour takes the value-form at all — why human labour should express itself as the objective value of a thing, and why that value should have to appear as exchange-value and finally as money. Marx's target across Part One is the form, not merely the magnitude, and the analysis is immanent: no external standard is imported, the commodity is made to yield its own contradictions, and each category is forced out of the insufficiency of the one before it. That is the through-line the reconstruction below follows — from the two factors of the commodity, through the dual character of labour, through the four forms of value to the money-form, and out into the fetish.

Marx sets the stakes in the Preface, and the brief takes his warning as its orientation. The difficulty is concentrated exactly where the payoff is.

Beginnings are always difficult in all sciences. The understanding of the first chapter, especially the section that contains the analysis of commodities, will therefore present the greatest difficulty.

Marx, Preface to the First Edition, page 89.

The reason the difficulty pays is that what is under the microscope in Chapter 1 is not a minor category but the germ-cell of the entire mode of production. The famous image is Marx's own, and it is the best statement of why Part One is load-bearing out of all proportion to its length.

Why? Because the complete body is easier to study than its cells. Moreover, in the analysis of economic forms neither microscopes nor chemical reagents are of assistance. The power of abstraction must replace both. But for bourgeois society, the commodity-form of the product of labour, or the value-form of the commodity, is the economic cell-form.

Marx, Preface to the First Edition, page 90.

The reconstruction runs Chapter 1 section by section, at full quotation density, because Chapter 1 is the anchor of the volume; Chapters 2 and 3 follow. What the brief does not do — weigh the derivation against later theories of value, or measure the value-form analysis for what it may occlude — is left to the researcher who has the reconstruction in hand.

1 · The Two Factors of the Commodity: Use-Value and Value

The volume opens not with capital, labour, or class but with the commodity, and the first sentence states why. Capitalist wealth does not present itself as a stock of use-values or as a sum of activity; it presents itself as a heap of saleable things, and the single commodity is the unit that heap is built from. The analysis therefore begins where the wealth first appears.