BOOK REVIEW / SCIENCE : Research Could Put Time on Our Side : INNER TIME: The Science of Body Clocks and What Makes Us Tick, <i> by Carol Orlock</i> , Birch Lane Press, $18.95, 208 pages

The tyranny of time began about a hundred years ago. Before then, with some exceptions, people worked until the job was done, and the day began and ended with the rising and setting of the sun.

Time varied arbitrarily between towns as close to each other as New York and Philadelphia until the serpent of knowledge brought the telegraph, telephone and railroads onto the scene and time zones were established. When the serpent switched on electric light, enabling people to work 24 hours at a stretch, time took on even greater importance. A science-fiction writer in 1893 saw the implications and described a civilization on Mars where people were paid in units of time instead of money.

Since then, time has ruled our lives. Biologists looked for and found clocklike mechanisms inside plants and animals that function even when the subjects were kept in the dark. After a while, physiologists studied human volunteers who, after living in caves for months, stopped keeping 24-hour days but replaced them with longer but still regular cycles. Biological clocks seem to be part of all life.

In “Inner Time,” Carol Orlock describes the discovery of these clocks during the development of the new science of chronobiology--a synthesis of comparative biology, sleep research, psychiatry, gynecology, fertility studies and even medical oncology. Orlock asserts that chronobiology arrived in the nick of time, just as the hectic pace of our global economy, two-career families, shift work and instant communication has come to threaten civilization’s stability.

This new science can help us, she implies, if we can understand the complexities of our body clocks and learn to control them.

Orlock guides us through the newly revealed hierarchy of body clocks, including clocks on the molecular and genetic levels and clocks that control three kinds of rhythms: the ultradian --cycles that recur often within a single day, sometimes within milliseconds, like the neurons that signal each other inside the brain; the circadian --cycles such as digestion that take about 24 hours, and the infradian --cycles that last a few weeks or more. While the best known infradian rhythm is a woman’s menstrual cycle, Orlock emphasizes that such rhythms also affect men.

The body-clock disorders Orlock describes include problems of jet lag, shift work and Delayed Sleep Phase Syndrome, a kind of insomnia common in adolescence.

Orlock frames her narrative in clever time-travel scenarios. At the start, she takes us back to our prehistoric ancestors--whose idea of time, she guesses, was probably a wheel of recycling seasons. Then she introduces a hypothetical couple living today who are so out of sync with each other, that it’s a wonder they ever found a mutually felicitous time to fall in love. At the conclusion, she fast-forwards to the 21st Century, where the offspring of this couple live blissfully with pills and light treatment keeping them in phase.

There is no turning back the clock for Orlock. She is not sentimental about the past. Instead, she offers a brave new world of artificial dawns and sunsets and melatonin pills--a hormone that affects the circadian rhythm--to combat jet lag. In her Utopian future, employers make chronoprofiles of their employees to set them on the most efficient schedule. Nothing is left to nature.

The most controversial findings that Orlock reports describe how attention to fluctuations in both body temperature and hormonal secretions over a 24-hour period and throughout the month can contribute to weight loss or gain, overcome infertility, help medications become most effective and even improve the efficacy of X-radiation or surgery.

Orlock, a journalist who writes for Lear’s magazine, presents a lot of anecdotal accounts of fascinating experiments in a breezy, accessible style. But because she doesn’t always identify the researchers, it may be hard to track down the studies. This is something a wise patient might want to consider before marching into a doctor’s office and demanding melatonin pills for jet lag or insisting on surgery at a certain time of day or night to get a statistical leg up on success.