In large part, they succeed. Byrd and Clayton tell a painful story, full of outrageous cruelty and neglect. The tale has been told before, but never in such depth or heartbreaking detail.

Byrd and Clayton argue persuasively that the poor health suffered by many blacks today has its roots in the treatment they received from slave traders and owners hundreds of years ago. Overworked, underfed, lacking immunity to the diseases they encountered on these shores, the earliest African-Americans suffered a “slave health deficit” that their ancestors have never been able to make up. Today blacks have a life expectancy five to seven years shorter than that of whites, more than double the rate of infant mortality and much higher incidences of diabetes, heart disease and certain cancers than the general population has.

In the dawning days of the new country, of course, doctors didn’t have much to offer. Blacks were probably grateful to be spared standard treatments such as sweatings and bloodlettings. As medicine advanced, however, and blacks continued to be denied the services of physicians, the gap between their health status and that of whites grew. An assumption developed, still detectable in news coverage and public policy decisions, that poor health was somehow normal for African-Americans, their natural state. This convenient expectation among whites became a self-fulfilling prophecy for blacks.

When doctors did pay visits to blacks, they came on orders from slave owners. Wary of the motives and loyalties of white physicians, and more comfortable with healers in their own traditions, blacks often resisted or ignored the prescriptions of plantation doctors. The authors demonstrate that blacks were suspicious of the medical profession long before the Tuskegee medical experiments and other 20th century horrors — with ample reason.

Byrd and Clayton show in unsparing detail how the white medical establishment mistreated blacks. Inexperienced doctors honed their skills on blacks before attempting to treat white patients. Medical schools used blacks for experiments and demonstrations. Hospitals and clinics turned away blacks or subjected them to substandard treatment in segregated wards. Professional organizations, including the American Medical Association, denied membership to the small number of African-American doctors. Many physicians enthusiastically contributed to the pseudoscientific literature on black inferiority. When African-American health further deteriorated following the Civil War, many doctors named the newfound freedom as the cause. Others predicted, or perhaps hoped, that the extinction of the race was near.

This shameful tale is an invaluable addition to our understanding of race and medicine. The problem is, the story occupies perhaps one-third of this nearly 600-page book. The rest is taken up with irrelevant information, endless repetition and unfathomably turgid prose. We are treated to a history of race and medicine from prehistoric times through the Renaissance. We are given pages of straight history about slavery, the Civil War and Reconstruction that would be more suitable for a social studies textbook. We’re told again and again what the book plans to do, what its “objectives” are; at the end, we’re taken through, point by point, what the book has accomplished. And we are given sentences like this one: “Such an approach effectively reveals and demonstrates this dilemma’s operational mechanisms from its history-based roots to its present configuration, which is deeply embedded within and permeates the U.S. health system and its culture.”

The authors insist that their excesses are necessary as a defense against racially motivated critiques. Because “any scholarship involving the reassessment of American concepts of race, Western history, or American history calls forth contentiousness, defensiveness, and avoidance of allegations of intellectual dishonesty,” Byrd and Clayton write, their book “may seem overdocumented, occasionally repetitive, or overburdened with endnotes and footnotes compared with conventional studies.” In one sly sentence they have patted themselves on the back for their thoroughness, set themselves up as brave warriors against the establishment and inoculated themselves against legitimate criticism.

Their odd mixture of incautious rhetoric and fastidious documentation produces some absurdities, such as a reference to “lily-white-owned and -operated health care corporations” that is accompanied by a footnote helpfully explaining that “lily white” means “excluding or seeking to exclude black people.” The authors hint at, though never quite espouse, a radical understanding of race in this country. They use quotation marks when referring to high school “achievement” tests or America’s “meritocracy,” and suggest that the failure of the government and the mainstream healthcare system to adequately consider the healthcare needs of minority groups “calls America’s democracy into question.”

The book is weakest when it abandons its scrupulous effort to reconstruct history and offers pronouncements on modern-day politics: “Anti-discrimination rules designed to protect disadvantaged minority groups such as Blacks and Native Americans, victims of centuries of invidious racial discrimination, are now used to protect Whites,” they charge. “Aggressive feminist and newly empowered Latino and Asian American groups” now “threaten to overpower the interests of America’s oldest and largest minority group.”

How much better if Byrd and Clayton had imposed discipline and focus on this bloated book. A lean, tight story could have taken their important and relevant message and run with it.

In an act of admirable honesty, or professional masochism, this second-generation obstetrician is particularly hard on his own specialty: His colleagues are too little concerned with patients, too taken with toys and gadgets and charge inflated fees for work that nurse-midwives could do just as well. “Obstetricians,” he announces, “are to routine prenatal care what neurosurgeons are to simple headaches: overkill.”

The crux of the problem, he says, is that we’ve turned a natural, normal condition — pregnancy — into a disease requiring doctors’ intervention. Expectant mothers are “considered sick until proven otherwise,” their pregnancies regarded as problems waiting to happen. The fact that they proceed perfectly well 97 percent of the time allows obstetricians to claim credit they haven’t earned, but also obscures the grim truth that when things go wrong there’s often little medicine can do. It’s a deeply unsettling message: We’d all like to think that our doctors are firmly in control and not, in Strong’s ruthless phrase, “hapless bystanders” — “heroes if all goes well or malpractice defendants if it doesn’t.”

Our need to believe that prenatal care really works has led us to rewrite the history of public health, says Strong. Falling rates of maternal death over the past century are often attributed to the spread of such care, when really they’re the result of more general medical advances, like improvements in surgical and blood-transfusion techniques and the development of antibiotics. In our own time, prenatal care is promoted as an answer to poverty, particularly among teenage mothers, but, as Strong notes, the problems of the poor are far too complex and deeply rooted to be addressed by a handful of visits to a clinic. In any case, those who would make prenatal care universally available are merely improving access “to a system that doesn’t work,” he states bluntly.

That system, in Strong’s view, is set up to benefit obstetricians, managed-care companies, malpractice lawyers — everyone but mothers and their babies. The results show up in disturbing national statistics: The United States ranks 31st among developed nations in its rate of low-birth-weight babies; 22 industrialized countries have infant mortality rates that are lower than that of the U.S.

“It is in the United States, where care is provided with such high-tech flourish, that pregnancy outcomes are among the worst,” Strong concludes. “We spend more for it, provide more of it and have intensified it more than any nation on Earth. In return, our prematurity, low-birth-weight and very low-birth-weight rates have accelerated.”

The author has a long list of proposed remedies, most of which boil down to this: “What is needed is a prenatal care system that is simpler, less medicalized and more widely distributed throughout our communities.”

Strong isn’t opposed to prenatal care itself, he emphasizes, just the form it currently takes. He’d like to see more smaller clinics, in convenient places like malls, churches and community centers. Such clinics would be open nights and weekends, and would be staffed with nurse-midwives rather than expensive obstetricians. He would reduce the number of visits required of women with low-risk pregnancies and would initiate malpractice reform, limiting damage awards and lawyers’ contingency fees.

All reasonable recommendations, and yet there’s something about Strong’s exhortations that chafe and arouse resistance. He’s pushing for a more humane kind of care, but his own manner is coldly austere, almost puritanical. In his zeal to prosecute doctors with high-profit practices, he shuns all hint of pleasure or sensuality, even ridiculing a magazine article that describes a prenatal clinic’s “comfortable, feminine, attractively decorated offices.”

Likewise, Strong can see no rationale for using the tools of obstetrics for anything other than strict medical necessity. “Everybody likes ultrasound — especially pregnant mothers,” he concedes. “But obstetric ultrasonography is frequently performed at the whim of obstetricians for no particular reason.”

Apparently, a pregnant woman’s pleasure and peace of mind at seeing her unborn baby don’t rise to the level of a “particular reason.” Patients’ state of mind, in fact, seems entirely irrelevant to Strong, who bases his proposal to reduce prenatal visits on evidence that an increased number of visits does not translate into lower infant-mortality rates. Never mind that such sessions are used not only to provide medical care but to allow expectant mothers to ask questions and receive support and reassurance. These intangibles are of no interest to Strong, who prefers to peruse his tables and charts of pregnancy outcomes. Being pregnant, after all, is not like having a broken bone splinted or an appendix removed; it involves the utter transformation of one body in the creation of another, a profound and joyful outcome the rest of us know as a baby.

It’s this paradox that’s exploited by neurosurgeon Frank T. Vertosick Jr. in his new book, “Why We Hurt: The Natural History of Pain.” Chapter by chapter, Vertosick introduces us to some of the more excruciating forms of pain, from the misery of migraines to the ache of rheumatoid arthritis. If this sounds about as fun as a trip to the dentist, the book will surprise you. With a humane and generous sensibility, Vertosick explores not only the nerves and neurotransmitters that direct pain, but how culture and belief shape the very experience of it.

In his view, for example, my friend violated an ancient social taboo when she told me the truth about her labor. Women throughout history and all over the world have developed methods, Vertosick writes, “for hiding the pain of childbirth from impressionable young females.” When they could, mothers-to-be “sought to give birth alone or with the aid of older (and often postmenopausal) women.” When crowded conditions made such withdrawal impossible, they cultivated a stoicism that made birthing look as effortless as blowing one’s nose. They even managed to fool many Western experts, who marveled at the ease with which “primitive” women popped out their babies. Childbirth pain, they concluded, was “an invention of pampered, out-of-shape white Europeans and could be cured by stripping them of their high society soft-headedness.”

Though this seems a bit shaky as anthropology — most women throughout the ages, after all, have not had much choice over whether or not to bear children — the theory is characteristic of Vertosick’s efforts to look beyond the physical manifestations of pain. Delivery is so painful, he reminds us, mostly because the birth canal must accommodate the human infant’s large head — the same head that houses our uniquely complex and brilliant brain. Likewise, it’s our powerful opposable thumbs that make us susceptible to carpal tunnel syndrome, and our improbably upright spines that expose us to the risk of ruptured discs.

To be human, in other words, is to hurt — or more precisely, to suffer, which Vertosick describes as the melding of biological pain with psychic pain. Because we can anticipate pain and its consequences (six weeks out of work, no more mountain biking), its effect is multiplied; because we can feel empathy for others, their pain becomes our own; because we can learn from our mistakes, pain imposes on us an inexorable discipline. I hurt, Vertosick might say, therefore I am.

But the author doesn’t take himself too seriously, and the book is edged with his sharp wit throughout. In describing an early lobotomy, Vertosick deadpans: “The operator inserted an ice pick under the upper eyelids and hit the pick with a small mallet to drive it into the frontal lobes. The operator then rotated the pick vigorously to destroy both lobes. This created a docile, albeit somewhat dull, patient.” The pioneering neurologist, he then notes, received the Nobel Prize for his invention.

Such squirm-inducing descriptions are a staple of the book, but Vertosick never resorts to sensationalism. After all, details as graphic as these require no embellishment. About a woman who could allay the pain of her migraines only by vomiting, he relates: “She had to stop the practice after a bad bout of retching detached one of her retinas and blinded her in the right eye.”

In documenting sufferers’ desperate search for relief, Vertosick is candid about the role played by reckless, careless or self-serving doctors, whose misguided attempts to banish pain read like a top-10 list of medical blunders. “During the last century and the first half of this century,” he writes, “many physicians thought that chronic pain could be cured by cutting nerves. If the face hurt, surgeons cut the nerves to the face; if the arm hurt, they severed the nerves to the arm.” More recently, in the 1980s, some orthopedists believed that injecting a powerful enzyme into diseased spinal discs would cause them to shrink, eliminating the need for back surgery. Unfortunately, notes Vertosick, the enzyme — a key ingredient in many meat tenderizers — “also dissolved other tissues, including muscles and nerves.” So much for that idea.

The author is refreshingly humble about his own work as a doctor — “most operations are fairly simpleminded,” he concedes — though he displays a surgeon’s affection for his handiwork, and occasionally imagines himself a cowboy in scrubs. Of an operation on a patient whose rheumatoid arthritis had caused her first vertebra, called “Atlas,” to shift out of alignment, Vertosick recounts: “I lassoed her wandering Atlas to the vertebra below with two thick braids of metal wire, then tossed in bone chips harvested from her hip for good measure.”

As a writer, Vertosick is just as confident, taking risks that pay off more often than not. When he described carpal tunnel syndrome as “modern stigmata,” I was skeptical: It’s hard to muster reverence for a secretary crucified on her keyboard. But the passage soon unfolded into a fascinating, if gruesome, historical account. The nails of ancient executioners were not driven through the palms, as depicted in most statues and paintings of Christ, but through the wrists at the base of the thumb: the carpal tunnel. Pontius Pilate achieved by more direct means the same incapacitating pain experienced by overzealous typists, whose nerves become pinched by ligament, tendon and bone.

Once in a while, Vertosick’s flights of fancy fall flat. His efforts to find out why we hurt often lead him to evolutionary theory, which he embraces without reservation. This line of thought produces some eminently plausible explanations — pain evolved to force us to rest a body part until it has healed, and to keep it away from substances that might infect the wound — and others that appear much more unlikely. It seems far-fetched, for example, that women’s hormonal cycles evolved to generate migraines at times when they are least fertile, in order to discourage unproductive sexual encounters (as amusing as a Darwinian rationale for “Sorry, dear, I have a headache” might be).

Still, you have to give Vertosick credit for trying. In a market glutted with guides for dummies and manuals for total idiots, he has dared to write an ambitious, intelligent book that addresses the mind as much as the body. In this, he follows the ancient Greek physician Hippocrates: “Medicine,” as Vertosick quotes him, “is the art of entertaining people until they heal themselves.”

Some aspects of this “revolutionary” thesis are already familiar. Freud also located love and its discontents in the body: All those female patients with their odd physical quirks, due always, it turned out, to some kink or twist in love’s free expression. But for Freud, the involvement of the body was the symptom, not the cure. That was achieved by nudging the neurosis out of the corporeal and into the abstract, where it could be looked at in the light. Lewis et al., meanwhile, move in the opposite direction: They want to return love to the body, show that it’s made from flesh, blood and bone.

Central to their argument is the theory of the “triune brain,” which holds that our minds are made up of three parts, each an artifact of a particular era in our evolutionary history. There’s the reptilian brain, which keeps our hearts beating and our lungs filling with air. There’s the limbic brain, peculiar to mammals, which regulates our relationships with other warm-blooded creatures. And there’s the neocortex, in humans the largest of the trio, which allows us to speak, reason and make up theories like this one.

It’s the middle, limbic, layer that runs our love lives, the authors assert, and it gets the whole body into the act: heartbeat, temperature, blood pressure, the flow of neurotransmitters, all are righted and steadied by the presence of someone we’re close to. And love alters not only these fleeting rhythms, but also the very structure of the brain. Every time we think, say or do something, we beat a path through neural thickets that makes it a little easier to go that way again. In love, especially, we tend to follow the tracks we’ve made before, and we look for others who inhabit familiar territory. To try to love someone whose mental highways and byways don’t intersect with our own — who sulks when we would argue, who shouts when we would cry — is to enter an emotional wilderness.

Love makes its mark on us early. In greenest childhood, the brain is busy pruning the lush overgrowth of synapses with which we’re born. Though this process is familiar to every ambitious parent (lay down some French verb tenses before it’s too late!), it’s less often applied to the emotional brain. But the same thing happens here: If a baby doesn’t encounter kindness and compassion in her first years of life, she’ll be no more conversant in its ways than any other latecomer struggling to master a foreign tongue.

Memory, too, becomes a physical part of us. There’s the explicit kind, which records in vivid but fast-fading detail the casual criticism your lover lobbed at you last night. And there’s implicit memory, which extracts from those details a general principle — people who love often hurt you — and squirrels it away for future reference. In childhood, especially, our implicit memories are engaged in identifying “rules” about how relationships work, and these unconscious rules are the ones we live by as adults.

In all these ways, the authors tell us, love permeates and saturates the body. A pleasing thought, until you consider what it means for those who have absorbed less-than-ideal notions about relationships and romance. They’re stuck, it would seem, since the limbic brain is utterly impervious to reason or analysis. There’s only one solution, say Thomas, Amini and Lannon: therapy.

Surprise, surprise. All three are practicing psychiatrists, and though they never acknowledge their self-interest in the perpetuation of therapy, it’s apparent enough. Helping patients learn how to have healthy relationships “takes vast vistas of time — three, five years, sometimes more,” they note sanguinely. It doesn’t much matter what words are said during these scores of sessions, they imply; what’s important is that a mysterious process takes place, something they call “revising limbic attractors.” What has until now been a vigorous and well-supported argument here softens into mush. “If patient and therapist are to proceed together down a curative path,” the authors intone, “they must allow limbic regulation and its companion moon, dependence, to make their revolutionary magic.” One can almost hear, thumping in the background, the drumbeats from one of Robert Bly’s wooded retreats.

To their credit, Thomas and the others recognize that forces larger than individual experience shape the way we love. But their discussion of cultural impediments to love is also oddly flawed, a random, eccentric collection of diatribes against phenomena as varied as corporate loyalty and the war on drugs. It includes, among other oddities, a five-page rant against children sleeping apart from their parents and a hysterical denunciation of HMOs that likens them to cannibalistic alligators.

The authors endlessly exhort us to spend more time with our spouses and children. That’s fine; most of us would like to do just that. But how to handle the intense pressures pushing us in the opposite direction? They offer only smug platitudes, assuring us that if we would “forgo exalted titles, glamorous friends, exotic vacations, washboard abs, designer everything,” we might “just get a chance at a decent life.”

Most troubling of all is their unspoken political agenda, one that might have been guessed from their enthusiastic endorsement by anti-feminist Danielle Crittenden. Thomas and his co-authors inveigh passionately against day care, and though they occasionally suggest that a “parent” ought to stay home with children, mostly they just say “mother” (and that gender-neutral parent always turns out, a few sentences later, to be a “she”). Quivering with indignation, they declare, “In its baldest tally of values, our culture automatically equates a dedication to full-time parenting with the absence of ambition. But in what human activity could there possibly be more?” Try professor of psychiatry at the University of California-San Francisco, a title held by all three men in addition to demanding schedules of writing and private practice. That’s not to discount their point, but to suggest that they pay too little heed to the complexity of women’s (and men’s) choices.

They conclude with an apocalyptic vision of America’s future. “Just as the dinosaur body was built to live within a range of temperature, so the limbic brain chains mammals to a certain emotional climate,” the authors maintain. “The giant reptiles vanished when the skies darkened and temperatures fell. Our downfall is equally assured if we push our living conditions beyond the limits our emotional heritage decrees.” But are those limits really so rigid? Human beings have thrived precisely because they are so intelligently flexible, able to adapt to “emotional climates” other than the sunny suburban skies over 1950s Levittown.

If their grim conception of what lies ahead is unconvincing, so, ultimately, is their idea of what grown-up relationships ought to look like. The authors would have us surrender to the swampy, symbiotic ways of the limbic brain, and ignore the edgy intrusions of the insistently verbal neocortex. But how do we get to know each other, after all, except through talk? New lovers can’t spill their secrets fast enough, and more familiar ones find that their running conversation, years or decades long, becomes the sum of what they share. Anyone who has loved another adult knows the primal, almost infantile comfort that a partner’s touch can provide. But they probably also know the pleasures of prickly individualism, of two personalities held just far enough apart to see each other whole — body and mind.