In an era of introspection, the human body has become a national pre-occupation -- from sex clinics to open heart surgery. Mostly we focus on what goes wrong. What distinguishes these two books is that they focus on what goes right. In fact, both are in their own way eulogies to the magnificence of the human machine.

Jonathan Miller's "The Body in Question" stems from a 13-part BBC series on the history of medicine. Its theme, as Miller takes his "chronological trudge from Hippocrates to Christiaan Barnard," is that medical breakthroughs are not brought about by the discovery of some new drug or surgical procedure, but by understanding how the body works. Medicine's level of understanding, moreover, is determined not by the amount of genius of any given physician but by contemporary technological development.

How could Galen, who worked on the problem in the second century A.D., have known that the heart functioned like a pump when such a machine did not appear on the scene until much later? However, by the 16th century the pump was widely used in mining, fire-fighting and civil engineering: Enter William Harvey in the early 1600s and the "discovery" of the propulsive role of the heart in circulating blood.

"The development of technology created a new stock of metaphors," Miller explains. "Once man succeeded in making equipment which performed -- looms, furnaces, forges, kilns, bellows, whistles and irrigation ditches -- he was confronted by mechanisms whose success or failure depended on the efficiency of their working parts... By mechanizing his practical world, man inadvertently paved the way to the mechanization of his theoretical world."

Clearly, as a historian Miller is a spokesman for the Age of Technology. Today a doctor looks at his or her patient much the way a space engineer analyzes the systems in a planetary probe. Miller stresses that it is the engineer's "systems" approach to biology -- not the technological devices themselves -- that account for medicine's success, and this success is very recent, only beginning in the middle of the 20th century.

Here Miller takes the middle ground in the debate over medicine's effectiveness. Antimedical thinkers like Ivan Illich, Rick J. Carlson or the historian Thomas McKeown point out that medicine for all its gimmicks -- from Darvon to body scanners -- actually has had little impact on over all health status. In fact, in some instances, medical treatments may do more harm than good. Meanwhile, those medical activists reinforced by the American health-care establishment believe that more medical care translates into better health and usually such care involves the most sophisticated technology applied to the patient.

In the midst of this debate, Miller sees signs that the antiscience tide is rising with the emergence of cults, the popularity of herbal remedies and soul-searching therapies. He sounds a warning cry at what he perceives as "a large-scale rejection of scientific thought."

Looking at history, Miller points to the ascendency of Christianity which dulled civilization's interest in the physical world for 1,000 years. Medical sciences slept. For example, Roman art of the pagan second century A.D., had showed the natural world in all its fullness; less than a few hundred years later, the human figure was "reduced to a flattened silhouette" -- no skin, no blood, no muscles, mere fully clothed phantoms floating toward the next world. Not until the 14th century did the body make a comeback.

In "The Body in Question," Miller adroitly brings together art, medicine and technology, writing with knowledge and wit.

In contrast, John Stewart Collis' "Living with a Stranger" is a much more superficial book written in a rambling, condescending manner. There's so much literary name-dropping, it's hard to sort out the biology.

In the chapter on senses, for instance, he points out that Sherlock Holmes believed a good detective could recognize at least 75 different smells. We also learn that Macaulay could recite the whole of "Paradise Lost" by heart and that E. M. Forster was virgin until the age of 29.

When he discusses the differences between men and women, Collis skins to an all-time sexist low by ascribing genius to superhuman energy produced by male hormones: "I do not think that any amount of extra time and freedom would make possible a woman Shakespeare or Beethoven," he writes. "I think the reason for this is physiological. Women, we must remember, produce mankind and are rather good at looking after mankind. Men cannot do the first and are not much good at the second. There is in some of them a greater energy than women can ever command, sometimes amounting to superhuman force. Surely the roots here is physiological, in the male hormones and genitals."

With the human body viewed like that, it's best it remain, like the title says, a stranger.