If you’ve heard it once, you’ve heard it a thousand times: 19th-century Chicago thrived because it became the commercial crossroads of the nation. But have you ever heard that this happened in part because Lake Michigan runs north and south and not east and west like Lake Erie?

“In a northern landscape that still lacked railroads,” writes Yale historian and ex-midwesterner William Cronon, “only water could move so large and heavy an object as a sawlog for any great distance. Fortunately, the same climate, glaciers, and impermeable bedrocks that had created soil conditions favorable to forest growth had also left the north woods with an intricate network of lakes, rivers, and streams. If one could only get the trunk of a pine tree to the bank of a major stream, water would do the work of carrying it to mill and market. Most of the timber-bearing rivers and streams of upper Michigan and northeastern Wisconsin flowed into Lake Michigan. With its northern end in the forest and its southern end three hundred miles away in the prairie, the lake was a natural corridor between two ecosystems. At one end were prairie people desperately short of trees; at the other, forest people who had more trees than they knew what to do with. . . . Ecology and economy had converged: the city lay not only on the border between forest and grassland but also on the happy margin between supply and demand.”

In Nature’s Metropolis: Chicago and the Great West, Cronon has written one of the all-time great books of Chicago history. And yet he names few individual Chicagoans and no Chicago politicians in its 530 pages. His thesis is almost a platitude–that Chicago and its “Great West” hinterland (a contemporary term describing Lake Michigan to the Rockies, or even the Pacific) grew up together, shaped each other, reflected each other. Hog butcher to the world, right? But Cronon’s research is so thorough, his explanations so deep, his sprinkling of evocative details so apt that the reader sees the “obvious” with new eyes, and sees unexpected connections to the not-so-obvious with amazement.

Cronon has an ulterior motive. “The book is not an environmentalist tract,” he said in a recent interview, “but it is intended to make environmentalists think very hard about their assumptions.” He quashes both the romantic view that the rural midwest (or rural anywhere) is a genuine alternative to the city, and the equally romantic view, expressed in 1898 by novelist Robert Herrick, that the city is “a stupendous piece of blasphemy against nature.” “Country good, city bad” makes no sense after reading Nature’s Metropolis. You might as well try to decide which part of the intersection of State and Madison belongs to State and which part to Madison.

The leading characters in Nature’s Metropolis are not people but commodities. Grain, lumber, meat, credit, and consumer goods turned Chicago from a minor fur-trading post in 1830 to a many-tentacled modern metropolis in 1890. At the same time they turned the rest of the midwest from a remote wilderness of forests, prairies, and swamps to a right-angled checkerboard of fields and roads, the breadbasket of the world.

Grain came first, and as Cronon tells the story it becomes perfectly clear why Chicago rose while Saint Louis and other would-be hubs, such as Cincinnati and Michigan City, fell. The early 19th-century settlers grew corn and wheat, but they had almost nowhere to sell the grain and few reasonable ways to get it there. People either ate it or turned it into something more portable, like pigs or alcohol.

Gradually a river trade grew up, and those farmers or merchants with access to a navigable waterway put their grain in standard-size sacks and shipped it downriver, usually to Saint Louis. That city’s broad Mississippi levee was crowded with grain sacks, laborers, buyers, and sellers at a time when the Chicago Board of Trade couldn’t draw a crowd. “The [Board of Trade] membership roll for a nine-day period in July 1851,” writes Cronon, “reveals that only one member showed up on four of the days; no one at all was present on four others. Even the offer of free refreshments failed to increase attendance.”

Railroads changed all this. And railroads converged on Chicago because the Great Lakes and the Erie Canal had already given the city better access to east-coast goods and financiers than other cities in prerailroad days. So Chicago came to seem the “natural” east end of western lines and the west end of eastern ones.

Railroads could go where rivers did not. More important, however, railroads created an incentive to use them. To ship by water all you needed was something that would float (as the young Abraham Lincoln learned when he and two friends hired out to build a flatboat and take it down to New Orleans in 1831). But to ship by rail you needed miles of steel rails, thousands of ties, and hundreds of locomotives and cars. They were expensive, and they cost about the same whether they were working or idle. Thus efficient use of the system made a much bigger monetary difference on the rails than it did on the water.

Grain sacks had worked out fine in the river trade. Laborers could lift and shift them, and they could be piled in odd-shaped spaces below the decks. They also kept each farmer’s grain from being mixed with anyone else’s. “When shippers completed their final sales, they sold the rights to actual sacks of physical grain. A farm family sending a load of wheat from Illinois to New York could still have recovered that same wheat, packed with a bill of lading inside its original sacks, in a Manhattan warehouse several weeks later.”

Railroaders had to ship more grain faster. The steam-powered grain elevator enabled them to do so. Invented in Buffalo in 1842, the grain elevator became an essential part of the railroad-based Chicago markets in the 1850s. These tall, heavily reinforced structures stored grain in bulk and made it possible for Chicago merchants to benefit from economies of scale. Now they could receive and ship grain much faster, with far less labor, and therefore at about one-tenth the cost of shipping via Saint Louis. (Saint Louis was late in getting rail connections to the east, and river shippers had little incentive to increase the volume of grain handled.)

But the elevators could not cope with individual sacks of wheat or corn. “Grain entering Chicago might arrive in wagons or canalboats or railroad cars,” writes Cronon, “but to move up an elevator’s conveyor belts, it had to be sackless. Only then could corn or wheat cease to act like solid objects and begin to behave more like liquids: golden streams that flowed like water.”

But no sacks meant that all grain would be dumped into the same hopper. Small dirty nubbins swept from one farmer’s barn floor would mix with premium golden kernels from a neighbor’s. Why should anyone buy Chicago grain on this uncertain basis?

The Chicago Board of Trade solved this problem in 1856 with a set of regulations designating three categories of wheat–white winter wheat, red winter wheat, and spring wheat–and setting standards of quality for each. “In this seemingly trivial action,” writes Cronon, “lay the solution to the elevator operators’ dilemma about mixing different owners’ grain in single bins. As long as one treated a shipment of wheat or corn as if it possessed unique characteristics that distinguished it from all other lots of grain, mixing was impossible. But if instead a shipment represented a particular “grade’ of grain, then there was no harm in mixing it with other grain of the same grade. Farmers and shippers delivered grain to a warehouse and got in return a receipt that they or anyone else could redeem at will. Anyone who gave the receipt back to the elevator got in return not the original lot of grain but an equal quantity of equally graded grain. . . . the grading system allowed elevators to sever the link between ownership rights and physical grain, with a host of unanticipated consequences. . . .

“The changes in Chicago’s markets suddenly made it possible for people to buy and sell grain not as the physical product of human labor on a particular tract of prairie earth but as an abstract claim on the golden stream flowing through the city’s elevators.”

Insofar as such a big juicy book can be about one thing, this is it. What tied Chicago to its hinterland–and made them both what they are today–was the crucial transformation of particular physical things into interchangeable abstract commodities. As a result, large-scale farming became profitable–the lure of the Chicago market meant the demise of subsistence farms and virgin prairie alike–and the Board of Trade flourished. The north woods’ white pines–Thoreau’s “great harps on which the wind makes music”–became pieces of lumber to be sold for prairie farmhouses, wagons, and equipment; the South Branch of the Chicago River flowed through “a world that appeared to consist almost entirely of stacked wood.” Chicago meat packers turned hogs and cattle into food and clothing in such a way that “one hardly thought of the prairie or the plains while making one’s purchase, any more than one thought about Packingtown, with its Bubbly Creek and its stinking air. Meat was a neatly wrapped package one bought at the market. Nature did not have much to do with it.” The enlarged market forged new and unexpected connections–grain futures, for instance, became imaginable only after grain sacks had been eliminated–and at the same time obscured others.

This looks like a big mistake to many of today’s environmentalists, who tend to feel that we’d all be better off if each of us were acquainted, so to speak, with the chicken our breakfast egg came from and the field that grew the oats in our cereal. Indirectly but powerfully, Cronon’s book challenges this feeling.

He explicitly counters his own youthful impression that Chicago’s “orange cloud” of factory pollution was a nasty blot on the landscape that had no connection with his family’s bucolic retreat in Green Lake, Wisconsin. As his book demonstrates, this vacation area could not exist without its industrial underpinnings, without lumber, plumbing, heating fuel, access roads, and visitors. All would be in short supply without some kind of central commercial hub.

Cronon does not address the more sophisticated view, held by some environmentalists, that the entire complicated system of buyers and sellers he’s described is based on a terrible error–the view that nature should be held sacred, not turned into commodities bought and sold for profit. But the avalanche of fascinating detail in Nature’s Metropolis makes his disagreement with this position pretty clear.

Even in its 19th-century form, the economic machine Cronon describes is so interconnected and so pervasive that the idea of rebuilding from scratch now along “bioregional” or “deep ecology” lines makes no sense. Asked to elaborate, Cronon said, “What worries me most about modern environmental politics is its emphasis on global change. I find that immensely disempowering. There isn’t one big problem called ‘the environment,’ or one big market called ‘Chicago.’ That’s why the book is organized in smaller sets of causes and effects. If you ask only, ‘How can we preserve the white-pine forest?’ you can find answers–and in fact we do lumber in a much more responsible way now than 100 years ago, purely by market mechanisms.

“I do think that inattention to consequences and connections is one of the most troubling aspects of how we live. But we shouldn’t go back to grain in sacks. That would be crazy. Any mature response will have to be a complicated and partial one; the world is more complex than we think.”

Nature’s Metropolis: Chicago and the Great West by William Cronon, W.W. Norton & Company, $27.50.

Art accompanying story in printed newspaper (not available in this archive): illustration/Madeleine Avirov.