By Diane Ackerman

Random House. 235 pp. $23.95

Reviewed by David Guy

Diane Ackerman is like no other writer I have ever encountered. She writes a swiftly moving and sensuous prose that is extremely accessible but also reflects the encyclopedic knowledge and attention to minutiae of a laboratory scientist. Where does she get this stuff?, I say to myself time and again as I make my way through her work. She holds the all-time record for including details that I have had to wander off and tell my wife. It's a shame she didn't write the science textbooks I was forced to wade through as a kid. I might have learned something.

She is a master of the startling, substantial and often fascinating digression. In this book's second chapter, for instance, ostensibly about purification and atonement, she is riding her bike -- already we seem to have strayed -- when she notices her hand on the handlebar, and we get a paragraph about hands. ("Nerves in our hands send messages about touch, pressure, heat, cold, and pain up 17,000 fibers to the brain.") She muses that she could be riding this road on a horse, and we get several pages on the history of horses in human culture. The playfulness of horses reminds her of -- you'll never guess -- dolphins, and we get a substantial account of her frolic with a school of talented dolphins:

"Taking a striped, pink-and-purple ribbon from the end of my long braid, I let it float within eyeshot of a dolphin. In a flash, the dolphin grabbed the ribbon, then tossed it up, caught it with a flipper, tossed it backward, kicked it with its tail, caught it with the other flipper, spun around, slid it over its nose, swam away with it, then returned a moment later and let it fall through the water like a cast-off toy."

All of this can be as annoying as it is fascinating: Does the function of the hand, or the history of the horse, really have anything to do with atonement? It sometimes seems as if she has researched these topics and she is, by God, going to get them into her book no matter what. And there are times, when she moves from the Lascaux cave paintings of 30,000 years ago to an elaborate description of the Grand Canyon to a brief biography of Paul Gauguin when we want to throw up our hands and say, "What are we talking about here? I'm lost."

Ackerman's best work chooses broad topics in which she can wander freely. A Natural History of the Senses, for instance, takes up the apparently obvious subject of the five senses and drops one fascinating detail after another. After a while we don't care what sense we're dealing with or where we are in the journey. We're just reveling in the information and the delightful prose.

I found Deep Play more frustrating, largely because the topic seemed so interesting that I didn't want her to wander. By play she is referring to the activity that many of our most interesting people -- creative artists, religious mystics, serious athletes, explorers and thrill seekers -- take up as the major activity of their lives. Deep play takes place when this activity leads to transcendence, when the ego disappears and we are one with the activity. The dancer is the dance.

What Ackerman is talking about is the goal of various spiritual practices, like meditation, yoga, chanting, Sufi whirling. She is pointing out that it doesn't just occur in religious practice but is religious whenever it does occur, and she is right. Anything we do with our fullest self is religious.

But it is just because this subject is so compelling that the digressions seem so annoying: her stints as a soccer reporter and writing teacher, a brief biography of Carl Sagan, a rehash of her treatise on colors in A Natural History of the Senses, any number of forays on her bicycle. Her occasional glances back at the larger topic didn't make me feel we were sticking to the topic; they just made me wish we could get back.

Deep Play might best be read as a journey through the mind and sensibility of Diane Ackerman, with occasional reflections on the subject of play (often not too deep). That way, one might really enjoy the digressions, because the writing is as good as ever. But I can't help thinking she has taken up a fascinating subject only to leave it largely unexamined. She can't seem to resist the lure of endless trivia.

David Guy's most recent book is "The Red Thread of Passion: Spirituality and the Paradox of Sex."