WITNESSES FROM THE GRAVE

The Stories Bones Tell

By Christopher Joyce and Eric Stover

Little, Brown. 333 pp. $19.95

"DEAD MEN tell no tales," the bad guys in westerns used to say. But this engrossing scientific biography introduces us to a tough hombre in cowboy boots who has devoted a lifetime to proving that just the opposite is true. In the hands of Clyde Collins Snow, human skeletons, and even fragments of skeletons, yield up detailed accounts of who they were in life and how they met their death.

Like the celluloid heroes he resembles, Snow, an Oklahoman, has more than once ambled into a notorious homicide case, handed the authorities just the proof needed to bring the culprit to justice, and moseyed off into the sunset, complete with 10-gallon hat and southwestern drawl. But his admirers don't have to ponder, "Who was that masked man?" He is accompanied in his work not by a faithful Indian companion, but by his reputation as the world's leading forensic anthropologist.

Physical anthropology is not, at first glance, the stuff of high adventure. Snow's specialty, for example, is literally as dry as dust: the meticulous measurement of bones, often exhumed from unmarked graves. But from the charts and tables and calipers and X-rays, from the equations and diagrams, he and his colleagues have drawn some pretty stunning conclusions: new insights into Custer's fatal blunder; the certainty that Josef Mengele, Auschwitz's "Angel of Death," had indeed met the fate he inflicted on so many others; the identities of innocents "disappeared" by the Argentinian dictatorship.

Snow may be the science's most colorful practitioner, but he is hardly its first. For well over a century men and women have applied state-of-the-art science to unravelling the fate and identities of crime and disaster victims, war dead, lost wayfarers and sundry occupants of unmarked graves. And in this case the "and women" is more than an empty courtesy. Following World War II and Korea, anatomy professor Mildred Trotter modernized the 50-year-old French methods then used to establish a skeleton's height and broadened them to apply to the much more heterogeneous American war dead. And sculptor Betty Pat Gatliff has helped perfect the technique of reconstructing faces on skulls. These may sound like esoteric accomplishments, but they don't seem that way to families that would otherwise never know the fate of a loved one.

Authors Joyce and Stover ably combine a history of the science and a lucid survey of its principles and techniques with the biography of a memorable man. Thus we see methods of identifying individuals advance from vague notions that "criminal types" have certain kinds of gaits and eyebrows -- ideas that once seemed as authoritative as they now seem ridiculous -- to today's precise video-matching of skulls with the faces they used to wear. We learn how fingerprinting replaced an ingenious but complicated system of measurements as the gold standard of identify; we see dental X-rays become instruments of justice; we learn how bones disclose age, sex and race.

And we watch experts solve exciting cases. Snow travels to Bolivia, where he establishes that "mysterious" deaths at prison camps were in fact murders. He joins a team of pathologists, dentists, and other specialists in the grisly task of giving names to the victims of a major air crash. He helps identify the boys buried beneath the house of Chicago mass murderer John Wayne Gacy. He helps establish the death of Mengele beyond a shadow of a doubt, the last uncertainty having been removed when a colleague tracks down a certain Japanese-Brazilian dentist who administered the doctor's last dental X-rays. As each plot thickens, Joyce and Stover lay out the mystery involved, the methods used to solve it, the science behind those methods, and the history of their development.

And then, in the stirring climax, Snow exercises his powers in the noble cause of truth and freedom for Argentina, the country that made "to disappear" a transitive verb. For nearly a decade, under the tyranny of a military junta, officially sanctioned death squads "disappeared" thousands of citizens for such offenses as saying the wrong thing, belonging to the wrong club, and having the wrong friends. Confident that anonymous graves would remain so forever, the thugs filled the nation's cemeteries with acres of their victims. They scorned the valiant Mothers and Grandmothers of the Plaza de Mayo, who demanded, in the face of danger and for years on end, that the authorities account for their lost children and grandchildren.

But the murders didn't reckon on the return of democracy and the arrival of Clyde Snow. During arduous months in Argentine graveyards and laboratories, he provided the evidence that sent former bigwigs to prison. And he taught his methods to a dedicated team of young people, who continued the work of giving back to nameless murdered corpses the identities that had been stolen from them.

So dead men, it turns out, have a great deal to say, once we know how to listen. "Although they speak softly," Snow says, "they never lie and they never forget." They speak just loudly enough, it turns out, for justice to hear them.

Beryl Lieff Benderly is the author, most recently, of "The Myth of Two Minds: What Gender Means and Doesn't Mean."