Tim Walker covers business for Hoover's Inc. and is a doctoral student in American history at the University of Texas.

Jared Diamond's "Collapse" is an impressive work of history. It is broad in its learning and vast in its scope. It is written in a fluent narrative voice that would be the envy of many novelists. And it might actually make a difference in how people think about the world. It is, in short, a book that no self-respecting historian would write.

For a while now, the trend among academic historians has been to produce microstudies marked by narrow focus and exhausting theoretical rigor. When historians do work on a larger canvas, they tend to portray big, obvious topics -- lives of presidents, major wars or famous incidents such as the Lewis and Clark expedition. The kind of innovative megastudies that Diamond pursues are disdained as too broad, too ambitious -- beyond the reach of any properly strait-laced specialist.

Thank goodness Diamond is not a historian by profession. He is a scientist and, even by the lights of science, a polymath -- an ornithologist, physiologist, evolutionary biologist and biogeographer. As such, he is not subject to the narrow dictates of the historical profession, which means he is free to write the sort of history that a lay audience -- an intelligent lay audience, mind you -- is interested in reading. This was demonstrated by the huge sales and Pulitzer honors won by his last book, "Guns, Germs and Steel: The Fates of Human Societies." That subtitle almost seems like a slap at the historical establishment's allergy to master narratives, but it aptly reflects Diamond's devotion to what he calls "history's broadest pattern."

"Collapse," the latest result of Diamond's interest in the big picture, is a cautionary, but far from gloomy, tale that elevates the tone of environmental debate above fearmongering and ideological squabbles. Where "Guns, Germs and Steel" explored why certain societies managed to conquer large parts of the world, this one studies the reasons -- particularly the ecological reasons -- why certain societies have failed.

To elaborate his ideas, Diamond considers several collapsed civilizations, including those of Easter Island, the Anasazi, the Maya and the Greenland Norse. In each case study, Diamond draws on the work of specialists, from anthropologists to pollen scientists, to build a picture of why and how each civilization came to ruin. In the case of Easter Island, for example, he shows how islanders' religious beliefs, tribal allegiances, and use of the land -- all of which played a role in the creation of the island's famous stone statues -- reinforced one another in a vicious circle that led to deforestation, extinction of food species and, finally, civil war and population collapse. (Again tipping his hand as a nonhistorian historian, Diamond enlivens his case studies by frequently sharing his emotions. He opens one chapter with the admission that "No other site I have visited made such a ghostly impression on me as Rano Raraku, the quarry on Easter Island where its famous gigantic stone statues were carved.")

Diamond gives brief attention to societies that managed to solve problems of isolation, climate change, population pressure and social turmoil, such as Iceland, New Guinea and Japan, and then turns to several current societies that suffer from these same threats. For example, Diamond offers the case of Hispaniola, where the Dominican Republic shows signs of sustainable growth while Haiti suffers from an environment as poor as its economy. Haiti's past leaders enacted laws that drastically limited foreign ownership of property but never limited the population's use of trees for fuel. By contrast, longtime Dominican dictator Joaquin Balaguer actively sought foreign investment, outlawed logging, strengthened the country's robust system of national parks and subsidized gas stoves to reduce pressure on Dominican forests.

The last section of "Collapse" departs markedly from most current works of history. While many environmental historians write postscripts about how their studies relate to larger themes, these chapters are often long on generalities and short on policy specifics. Diamond, by contrast, devotes three long chapters to the lessons learned from his far-flung studies. He traces past societies' downward spirals to a small set of reasons: "failure to anticipate a problem, failure to perceive it once it has arisen, failure to attempt to solve it after it has been perceived, and failure to succeed in attempts to solve it."

To his credit, Diamond doesn't demonize the world of commerce. He's a passionate environmentalist, but also a passionate realist. "If environmentalists aren't willing to engage with big businesses, which are among the most powerful forces in the modern world, it won't be possible to solve the world's environmental problems," he writes. Given the sorry track record of many environmentalists on this score, the point bears repeating.

Diamond's final chapter lays out a dozen of the world's worst environmental threats -- destruction of natural habitat, chemical pollution, water shortages and so on. In the book's most practical turn, he lists and rebuts a slew of typical one-liner objections such as "Environmentalists are always crying wolf." One of his best rebuttals counters the claim that "Technology will solve our problems." After noting that "All of our current problems are unintended negative consequences of our existing technology," Diamond delivers this withering rhetorical question: "What makes you think that, as of January 1, 2006, for the first time in human history, technology will miraculously stop causing new unanticipated problems while it just solves the problems that it previously produced?"

Diamond's central thesis is one of hope: Despite major threats to the global environment, societies can act wisely. Many of our ancestors certainly got it right: Intensive but sustainable agriculture was practiced for centuries in the highland valleys of New Guinea; deforestation in Japan was reversed by a succession of Tokugawa shoguns hundreds of years ago. We moderns have it even easier; the advance of scientific knowledge should heighten our ability to anticipate, perceive and solve such problems.

Of course, the customs of certain professions make it less likely that the necessary information will get out to the public at large. Perhaps Diamond's next book will boast the subtitle "How Certain Academic Disciplines Fail or Succeed."