Adopted in 1981, the Uniform Determination of Death Act states that in order to pronounce brain death, “the entire brain must cease to function, irreversibly.” But the act is silent on how this function is measured (in one study, 65 percent of physicians and nurses couldn’t identify the established criteria for brain death). Most physicians look at the brain stem, which controls heart and lung functions, but not the cortex, which coordinates consciousness. Teresi reports on an apparently unconscious patient who “could have been calculating the cross section of the bottom quark using Heisenberg’s matrices, and no amount of ice water squirted into her ear would have detected it.” The patient was unplugged, her organs harvested.

The Harvard criteria assume that the brain-dead will quickly move to conventional heart-lung death. But Teresi learns that the brain-dead can maintain a long list of bodily functions, including some sexual responses, stress responses to surgery and the ability to gestate a fetus.

After making a case that brain death is easily misdiagnosed and that death can be a construct of convenience, Teresi next places his body between the transplant team and patients who exist in a sort of “death lite” netherworld, with a non­responsive cortex but a functioning brain stem. And now things get really creepy. A tiny minority of patients in minimally conscious or persistent vegetative states have been known to sit up and speak. And one “locked in” patient (with a brain stem irreparably damaged but a healthy cortex) even wrote a best-selling book about his condition, “The Diving Bell and the Butterfly.” But the onus is on patients to prove they are aware or in pain. “We would all sleep better at night if we could believe that patients in unendurable situations were unaware, but that does not make it so,” Teresi writes. Off they go to be harvested, despite the potential for surgeons to be distracted by their “screaming during organ retrieval.”

This is strong stuff, and Teresi — the author of “Lost Discoveries” and the former editor of Science Digest and Omni — never backs off. He circles, probes and pokes. He needles physicians and bioethicists, and he provokes organ banks by agreeing to donate only if he can be guaranteed an anesthetic during the procedure. (When the organizations refuse, he considers commissioning two operations: the organ donation and then a face-lift. “I’d get my anesthetic, and I’d hold the face-lift.”)

Teresi consorts with death in many places: mortuaries, execution chambers, hospices, intensive-care units and a meeting room filled with people who’ve had near-death experiences. But he steers a wide berth around two important groups: grateful organ recipients and those who tend the persistently vegetative for years on end. If I’m reading Teresi right, no one who shows any sign of consciousness, and hasn’t clearly indicated he or she wants to die, should be unplugged. Where there’s life, there’s hope. But he gives extremely short shrift to quality-of-life issues. And while a resuscitated donor headed for the transplant table may receive “the best medical care of his life,” a vast majority of acutely ill patients on chronic ventilation units don’t improve. Their skin gradually breaks down, and their circulatory and renal systems are propped up until an infection finishes them off.