A PLAGUE OF FROGS: The Horrifying True Story.

A PLAGUE OF FORGS: The Horrifying True Story by William Souder Hyperion, $23.95

THIS IS A REVEALING AND important book, and you should begin by ignoring the subtitle. Something tells me it wasn't the author's choice: In fact, he's done a remarkably sober and meticulous job of following a story that's been misreported in almost every newspaper and on every TV station in the country. By book's end, it remains largely unclear what causes frog deformities and exactly how worried we should be about them--but we've instead been treated to a remarkable inside look at science trying to grapple with horribly complicated real-world problems.

In the summer of 1995, eight junior high school students on a field trip discovered a small pond on a Minnesota farm where a great many leopard frogs were missing their hind legs. They called the state government, stories began to appear in the newspapers, and soon Minnesota's environmental agency had a map showing similar reports from almost every county in the state. Other such sites began to show up across the Great Lakes region; a Canadian researcher announced that the same trend was evident in Quebec. What did it all mean? No one knew for sure, because no one knew if deformed frogs were rare, or what might cause the deformities, or if that unknown agent might harm humans as well. It was a scientific puzzle, and a particularly difficult one. A pond is filled with water; it's hard to break down that water into its thousands of different compounds and figure out if one of them is, in fact, a poison.

And it's here that William Souder, a freelance journalist living in the region where the first frogs were found, really rolls up his sleeves and goes to work. Instead of "covering" the story with a few calls to bureaucrats, he digs in for the long haul, traveling to a long series of small scientific meetings, talking almost daily with the principal investigators, and watching as the science develops.

Though the book is not judgmental, it's abundantly clear whom he respects and whom he doesn't. The state bureaucracy clearly manages to mishandle the case at almost every turn; one lesson this book teaches is that, at least in what amounts to an epidemiological investigation, you can have too much decentralization. You really want people for whom such an outbreak is not a once-in-a-lifetime event. The EPA comes off a little better, though its penchant for chasing trendy topics is clear. And unknown federal agencies like the National Institute of Environmental Health Science come off better yet.

The star players, though, are individual scientists, and the real drama comes as they face off against each other with their competing theories. From the start, Souder writes, there are two broad schools: those who think some chemical, most likely from a pesticide, lies at the root of the deformities; and those who think it's a parasite that has entered the frogs and caused their limbs to malform. The two theories represent two different worldviews: in the first, people are carelessly damaging all that lies around them; in the second, nature is a robust place where stuff simply happens all the time.

The researchers come together for scientific meetings that clarify the battlelines--and Souder makes it clear that at least some of the divisions come down to personalities. The chief advocate of the parasite position, Stanley Sessions, seems as arrogant and unpleasant a person as you would care to meet. And yet, as the story drags on, his case seems more persuasive. In fact, most Americans who were following the story probably thought it came to an end last spring when Sessions and a Stanford student published papers in Science demonstrating a strong parasite connection.

But as Souder convincingly demonstrates, that didn't really end the debate. There's plenty of evidence that doesn't fit the parasite theory, especially a huge set of Canadian data set showing deformed frogs in agricultural areas and healthy ones elsewhere. Apparently ultraviolet light plays a role in damaging at least some species; hence the erosion of the ozone layer might be a villain. The truth is, we don't know yet what is deforming frogs, and we don't know yet why amphibians in general are in decline, and we don't know when we will know. The science is still developing, and as Souder points out, "science as it is actually practiced in the everyday world is ... like a collection of medieval fiefdoms. Agencies and independent academics live and work in walled enclaves, among which communication and cooperation is possible, but often strained ... Scientists, it turns out, suffer the same human foibles as everyone else. They're driven by ambition, by money, by ego, and by the perverse impulse to succeed amid the wreckage of someone else's failure"

One conclusion you could draw from that description is that scientists never really figure out anything. But that would be wrong--with enough work, they usually do, even when the problems are horrendously complicated. The best example is global warming, which in 1990 was at the same battling-theories stage that frog research currently finds itself in. But climatologists, well-funded and pushed by national governments around the globe, figured out a way to organize their efforts and, by 1995, generate a consensus. (And in fact the one conclusive part of the frog story is that certain species of high-elevation toads have been killed off by global warming, which has transformed the Central American cloud forests where they lived.) The public, and certainly Congress, may still be confused by global warming, but scientists speak with confidence about it--their warnings of immediate peril are clear and unmistakable.

Other controversies remain unresolved. The frog case is one part of the growing global concern over endocrine disruptors, chemicals that mimic hormones and may disrupt reproductive systems, a concern that will eventually be better understood by science. Similar research battles are now erupting over the safety of genetically modified foods. "Eventually," of course, may come too late, and it almost certainly would make sense to take precautions now on the chance that such chemicals or techniques might be harmful. But at the very least, one hopes there are other clear-eyed journalists working as hard as Souder. For these are the most important kind of investigations going on in our world, endlessly more important than the investigations that transfix Washington so regularly. That almost no one bothers to do the work of really covering them is a kind of journalistic crime.

BILL MCKIBBEN is the author of a number of books, most recently, Hope, Human and Wild: True Stories of Living Lightly on the Earth.