King Lear said, “I know when one is dead and when one lives,” but he was wrong. In spite of his tests, Cordelia was irretrievably gone, destined to endure the bodily decay that is everyone's fate.

But not quite everyone. Occasionally, by chance or artifice, at least some parts of the soft tissue remain, sometimes to be discovered millennia later with wonder and admiration. We have come to call such preserved bodies mummies, a word derived from the name of the heavy tar, mumiya, that the Egyptians used in their embalming rites.

This is the subject that Heather Pringle presents with sensitivity, erudition, and wit in The Mummy Congress. In preparation for this book she spent a year traveling all over the world, talking to the experts, learning the lore, inspecting the remains. The result is a work that is both lucid and complex.

Even the title previews the ambiguities that are to come. The first chapter simply reports on an actual congress of mummy experts from all over the world, a triennial event, this one held in Arica, Chile. She describes the participants as a quirky and diverse band who listen to endless papers on a wide range of subjects from parasites to cloth weaving, snipe at each other's theories, and generally indulge what the author calls their “strange, lonely passion.” Many are amateurs who pay their own way.

They divide, of course, into two generally warring camps, as all human endeavors seemingly must. The Dissectionists, many of them medical doctors, immunologists, and anthropologists, want to perform autopsies to find out what those ancient people ate, what drugs they used, what diseases plagued them. Their justification is the supposed benefits to humanity that will result from their work. The Conservationists, on the other hand, many of them museum curators, see dissection as an assault of the dignity of human beings and a meaningless desctruction of valuable historical objects. They are the defenders of Art and Culture.

The other, more profound meaning of the term “mummy congress” in the title is revealed by the cover. There we see eight ghastly human forms, arranged as if waiting in line at some infernal DMV. This congress of mummies represents the few thousand lucky ones of all the many billions who have lived and died on this planet who have somehow escaped their bodies' dissolution.

So that there is no mistake about the reality of that dissolution, Pringle describes intimately what death brings to most of us: first the runaway action of our own enzymes, then the invasion of the bacteria, and finally the insects, whose larvae strip the bones of all its remaining soft tissue. In a few weeks, months at most, it is all over.

But by various means, natural and artificial, some bodies have remained whole, some so perfect that they seem to have defied the centuries. Of one Andean girl we read, “. . . her face was exquisitely beautiful. Her cheeks were plump and full with baby fat, her lips soft and round. She looked . . .as of her eyes would flutter open at any time.” The description is no poetic flight. There is a picture of her to prove the truth of the description.

Although mummies are found on every continent (including Antarctica, says Pringle, if you count the frozen remains of explorer Sir Robert Scott), the Egyptians are the acknowledged champions of the preservation arts. Their religious beliefs led them to mummify, not only kings and rulers, but common people as well, down even to dogs and cats. So common were the results of the embalmer's art that later Europeans ground them up for use as medicine, in the making of fine paper, and as a translucent pigment called “Egyptian brown,” much prized by some Renaissance painters.

The South Americans were not far behind in their attempts at body preservation . The Incas chose their most perfect girls just at the moment of their puberty and sacrificed them on the mountains to the gods of rain and growth. Some Japanese Buddhist ascetics have starved themselves to death, eating only resins designed to preserve their emaciated corpses. In our own era, the Soviets were so successful at keeping Lenin looking fresh in his glass case that other Communists, including Ho Chi Minh and Kim Il Sung, clamored for and got the same scientific treatment.

Sometimes, when beloved figures died on the road, so to speak, their followers improvised, with some success. Admiral Horatio Nelson, expiring at the Battle of Trafalgar, was preserved in a cask of brandy, and Alexander the Great made it back home immersed in honey.

Just as interesting are the accidental mummies, to which the author devotes several chapters. The bog people of Ireland and the Netherlands, apparently executed in large numbers for unknown reasons in the dreary swamps of those countries, escaped dissolution by the chemical composition of the sphagnum moss in which they were buried. Otzi, the six-thousand-year-old Alpine villager, just froze where he lay. Strangest of all were The Incorruptibles, more than a hundred by one estimate, saints and martyrs whose bodies miraculously avoided decay (though researchers have discovered that at least one, St. Margaret of Cotona, secretly underwent a embalming remarkably like the Egyptian process some short time after her death, and St. Clare turned out to be really a mannequin).

Pringle tells all such grisly details engagingly, mixing scientific explanation with quick portraits of mummologists she met in her investigative travels. Her best moments, however, come when she relates stories of more recent interactions between the long-term dead and the living, such as the “unrollings,” grand social and educational events at which Victorian audiences watched as ancient cadavers were exposed yard by yard. One memorable occasion occurred in Boston, when to great fanfare a supposed “Egyptian Princess” was unrolled, only to reveal clearly to the shocked onlookers that she was no lady, princess or not. The author tells with some zest about the cryonics industry of our own time, where for upwards of twenty thousand dollars the deceased is placed in a large “Starbuck's thermos” inside a vat of liquid nitrogen until such time as science can safely thaw him or her out; and Summum Bonum Amon Ra of Salt Lake City, who for only sixty thousand dollars or so will put you in a fiberglass sheathing for all eternity. Pets can be immortalized at a discount.

Ms. Pringle is admirably suited to the job of bringing this widely divergent topic to a general audience. Her journalistic skills are impressive, bordering on scholarship, and she writes with clarity, feeling, and wit. The Mummy Congress is worth a bit of anyone's attention.