John Boslough's slender work on the British cosmologist Stephen Hawking -- who many believe is the greatest physicist since Einstein -- suffers from a propensity to trivialize the human element in science. One couldn't conjure up a more riveting subject. Hawking is the leading force in cosmology, the effort to understand the nature and origins of the universe, and his contributions are nonpareil. He is also totally paralyzed and barely able to speak as a consequence of a motor-neuron disease (the same that afflicted baseball great Lou Gehrig). Hawking's exceptional brilliance and achievement, coupled with his total physical debilitation, is a rarity that cries out for extended, refined treatment, but Boslough simply fails to deliver.

In fairness, "Stephen Hawking's Universe" is not really about Hawking. It is actually a primer on cosmology, and Boslough handles this immensely complex topic competently. Writing about cosmology is especially challenging. The concepts and analytical tools routinely used are bizarre, virtually beyond our capacity to imagine. The idea that time and space were created along with the energy and matter of the universe; notions of black holes and "event horizons" and negative gravity; controversies over whether there is more than one universe, or what happened before 10-43 second after the Big Bang -- this is the stuff of cosmology. Not easy to explain. Yet, for the most part, Boslough has a good feel for the topic, ready to render it in simple language and images.

A brisk, step-by-step approach to Hawking's work is essential, because his own scope has been so vast. Hawking's mission is no less than a comprehensive attempt to "unify," or discover a common heritage for, the four disparate forces at work in the physical world, the "unification" that Einstein sought for 30 years but failed to achieve.

Three forces govern subatomic particles: electromagnetic, which keeps electrons revolving around nuclei; the strong force, which glues protons and neutrons together within nuclei; and the weak force, which causes radioactive decay in certain elements such as uranium. The fourth force in the universe, gravity, is too weak to affect atoms directly, but operates on a grander scale. Gravity, however, is not subject to the calculations of quantum mechanics, which accounts for the behavior of subatomic particles. Yet a unified field theory demands that all of the universe's forces be explicable in a consistent way, indeed, derive from an antecedent in the "singularity" existing an instant before the Big Bang.

"Although particle physicists may be coming close to a unified theory of the universe with the three forces that push and pull within the atom," Boslough writes, "gravitation is still the odd force out. And this despite the fact that the vast world of cosmology and the tiny universe within the atom are finally converging as particle physicists looking inward with their giant accelerators and cosmologists looking outward with their telescopes begin to realize they are looking at the same thing."

As Boslough explains, Hawking has made numerous contributions to this search; in particular, his work with black holes -- the superdense dead stars in which gravity is so great that not even light can escape its grasp -- has advanced cosmology by leaps and bounds. And Hawking is confident that the unified theory will be uncovered in this century.

This is, to put it mildly, a remarkable endeavor, appealing to an ancient urge to learn of our ultimate origins. It is also a tale often told by storytellers more accomplished than Boslough. What would have distinguished this book is more about Hawking himself, as the subtitle promised. Boslough begins with some very brief anecdotes of Hawking -- when the disease was discovered, his family life and the like -- but then opts for a thin history of Hawking's contributions to cosmology. The author alludes to the idea of Hawking as a totally "cerebral man," one who has only his brilliant mind to occupy him, but this promising notion -- does it account for his achievement and celebrity? -- is never developed. Instead, the personal glimpses of Hawking are either fawning or banal.

The notion that Hawking's work and theories are controversial, even debatable, within the scientific community is scarcely mentioned. We learn little about how this most esoteric science really progresses, nor how Hawking's complex mathematical speculations might translate into a better understanding of the ordinary world.

What is really lost in this book, however, is Hawking himself, perhaps the most remarkable scientific mind of our times. "Stephen Hawking's Universe" would have been so much finer had it given us more of Stephen Hawking and less of the universe.