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When we write about food, the accounts are generally superficial, analogous to the way we cast our politics as celebrity and glitter. We ponder sauces and seasoning, but ignore the flow of real power that lies beneath. This is especially odd, given that food is so fundamentally significant to the human endeavor, the one story each and every one of the 6.865 billion of us engages directly and daily, the luckiest among us three times a day, with sauces and seasoning.

Nonetheless, when somebody does delve deeply into this story, the telling can enlighten, entertain, and unsettle. Such is the case with Empires of Food: Feast, Famine, and the Rise and Fall of Civilizations by Evan D. G. Fraser, an academic specializing in farming, climate change, and the environment, and Andrew Rimas, a journalist based in Boston.

Books about empires rising and falling are enjoying something of a renaissance. Yet this one is a departure from the usual accounts of the vanities of emperors and the perfidies of inbred monarchs. Fraser and Rimas's overarching argument is that the meat and potatoes of history is, well...meat and potatoes. Or to be more precise, it is about that weird co-evolved relationship between humans and a few botanically freakish grasses we call grains, which is to say, it is about agriculture. This is what distinguishes their effort from the current spate of books excoriating factory farms, feedlots, agribusiness, and fast food.

The most useful among the many useful messages of Empires of Food is that our manifest problems and crises are not new. The Eric Schlossers and Michael Pollans of the world, by and large, worry about the deleterious effects of modern, industrial, hydrocarbon-based farming on our health, the environment, and the integrity of our society. This is clearly worth worrying about, and these authors have struck a chord that needed to be struck.

Still, much of this work assumes that if we'd just go back to the way grandpa did it, we'd be fine. Not so, say Fraser and Rimas. The crisis of sustainability that looms just off the end of our forks has been a long time coming. Their important contribution is to demonstrate that these troubles did not begin with hybrid seed, anhydrous ammonia fertilizers, and high fructose corn syrup. The flaw of agriculture is inherent and fatal, based in the depletion of soil. The phrase "sustainable agriculture" has every bit as much meaning as "clean coal."

The book surveys a vast historical landscape, not in a linear plod but as an elegant buffet spread across space and time, leaping from odes to cereal by Hou Ji, the "Prince of Millet" in China 3,000 years ago, to the construction of the Three Gorges dam for the irrigation of cropland, from the reworking of Dark Ages Europe by Benedictine monks growing hops as a preservative for beer to the agricultural practices of the ancient Sumerians, who created the Fertile Crescent by turning the swamps around the Tigris and Euphrates rivers into farmland. All of this is wound up in the waxing and waning of empires, a process that is driven by agriculture.

The authors shanghai one particular character to loosely pull a narrative thread, an Italian named Francesco Carletti, born in Florence in 1573. The Mediterranean people were then buoyed by maritime discoveries and, more important, were in need of food because their own cropland had been depleted, so they had both motive and means to create a food empire. Carletti went along for the ride.

The authors use him as a physician would use a dye or a radioactive marker to trace a patient's circulatory system. His appearances, each of which illuminates a critical moment in the history of empire, are emblematic of the book's larger strength: wherever the tale goes in time and space, the story is the same. The waxing and waning of empires is rooted in agriculture.

It may seem self-evident to argue that the course of human history is driven by food, but there is something far more interesting at play here. Human history, after all, encompasses something like 200,000 years, but for at least 95 percent of that time humans have eaten only what they hunted and gathered. Before plant domestication, there were no empires, monarchs, irrigation, saved seeds, or global travelers like Carletti.

What the authors understand better than most is that the very botanical fundaments of this odd experiment dictate the course of history, the fatal flaw, and it is simple as dirt. The cultivation of grain -- wheat, corn, and rice, the sources today of the vast majority of human nutrition -- inexorably depletes the soil. We have always grown grain in monocultures of annual grasses, an unsustainable strategy that nature abhors. Agriculture depletes not through oversight, negligence, or greed, but inevitably.

At the same time, cultivation generates surplus, making possible the storage of that surplus and the creation of wealth. Farmers grow grains and sell their surplus to neighbors, who make a city. The soil is exhausted, and the city goes hungry, but has the might to go hunting for more -- in other words, to build an empire. This cycle is all of history.

The soil depletion that was the root cause of the waxing and waning of all the world's empires remains in effect, although the context has changed. The empires of the past overcame depletion by imperialism. Wear out your own soil, then raise an army and take someone else's, a strategy limited only by the technology that supported supply lines. As that technology became virtually unlimited, though, so did the size of empires.

But then, about 1960, everybody else's land had been taken, an inconvenient truth that humanity avoided by attempting to offset land depletion with chemical fertilizers. New limit: chemical fertilizers are energy intensive. "Bargain-priced energy is the reason we've been free to breed and feed our population past the 6 billion tally," the authors write. "Remove the energy, and those billions, too, will be taken away."

They provide examples of what this might look like, pointing out that in one period of decline of the European food empire (following the collapse of Rome, which the authors say was caused by soil depletion as well as by the Visigoths), Europe's population halved. Can't happen today? Remember: China starved to death as many as 30 million people in the 1960s. Ostensibly, that famine resulted from Mao Zedong's stupidity, but a dense and enormous population dependent on agriculture left the country vulnerable to that stupidity.

The history of civilization is one of expansion regularly punctuated by collapse and famine. This gets us to the inevitable conclusion of the authors' argument that agriculture is fatally flawed. The principles that drove the rise and fall of civilizations throughout the world's short experiment with agriculture remain in play. So does the relative scale of catastrophe.

The vast sweep of this idea is the greatest value of the book and the necessary corrective for the narrow focus of foodies. The authors, in fact, aim particularly vituperative blows at the Slow Food movement: "Slow Food is ostensibly about sustenance, fellowship, and democracy," they write, "but its face is the truffle-sniffing snout of the eco-foodie."

Of course, people reserve their harshest critiques for their best friends. The foodies aren't wrong, just too narrowly focused. The authors are roughest on them because they believe, as I do, that the foodies are on to something vitally important beyond the boutique, especially in eating local. Remember the role of supply chains and transportation in building empires and in driving the cycle of collapse. Eating local subverts the force that builds empires.

The authors extrapolate from this something like a solution, something useful beyond the gloom and doom, by bringing us back to the fundamental principles of surplus, transportation, and storage. Anything we can do to undermine any part of that triad undermines the entire cycle, which is why eating local is important. But this only begins to head us in the right direction. Until we address the fundamental flaw by redesigning agriculture to grow perennial plants in polyculture, there's no justification for getting smug about grazing on the organic radicchio in one's own foodshed.

Rimas and Fraser have a firm enough grasp of history and the enormity of the problems in play to forgo pat solutions. A problem that has been 10,000 years in the making and lies at the very heart of human civilization is not going to be solved without significantly disrupting life as we know it. Absent the truly revolutionary redesign of agriculture -- and present the 6.865 billion -- we will continue to reap what we have sown.