The best-known popular books about the origin of the universe may be Stephen Hawking's "A Brief History of Time," famous largely because it quotes his publisher's advice that every mathematical equation cuts sales in half, and Steven Weinberg's "The First Three Minutes," famous (or infamous) for his conclusion that "The more the universe seems comprehensible, the more it also seems pointless."



In "After the Beginning," Norman Glendenning, like Hawking and Weinberg a theoretical physicist, differs with both their points of view. His enlightening, entertaining, sometimes startling story tells how philosophers, astronomers, and physicists have teased out cosmic history right back to the first 10-to-the-minus-43rd of a second, before which time, he observes, we can't know anything, because the laws of physics didn't apply. (His title can be read as a commentary on astronomer Martin Rees's quite different approach in "Before the Beginning: Our Universe and Others.")



For the most part Glendenning's narrative is equation free, but unlike Hawking, he provides plenty of equations for those who really want them. In some cases the mathematical arguments in the boxes that follow key chapters actually make "After the Beginning" easier to understand than the opaque prose in "A Short History of Time"; in any event the equations can be ignored without impeding the narrative flow.



As for Weinberg, Glendenning is more cheerful by nature. To find the universe pointless is not, after all, a logical necessity, and in all that has happened since Weinberg's book was last revised in 1993, Glendenning finds anything but anxiety, notwithstanding that, if anything, the universe is less comprehensible than it seemed a decade ago. For at that time the great mystery of dark energy, which accounts for 70 percent of the density of the universe, was as yet unsuspected. Such new mysteries on the grand scale are balanced by new mysteries on the microscopic scale, of supersymmetry, string theory, and hidden dimensions.



"The men and women among us who in earlier times would have been priests and priestesses," he writes, "have been able to recognize the very seeds of the galaxies. One of these alone, the Milky Way, harbors billions of suns with billions of planets. From one small planet, the Earth, we look out in wonder."



Glendenning revels in the latest discoveries while laying the groundwork to appreciate them, not least with anecdotes of historical figures, some from the distant past ("The great tide of Alexander's conquests that soon swept over Asia and India often obscures what is important to our story of cosmology -- an end to the independence of the Greek cities and to the spirit of free inquiry of their citizens") and many more recent. For example, it was Paul Dirac's loneliness and depression, Glendenning suggests, that led indirectly to Dirac's insights linking quantum mechanics and general relativity.



The personal approach benefits greatly from Glendenning's long tenure at Lawrence Berkeley National Laboratory, from his familiarity with machines like the Bevatron, once the world's most powerful accelerator, where the antiproton and antineutron were first detected, and from his aquaintanceship with leading players in the still unfolding story of the cosmos there, scientists like George Smoot, who pioneered studies of the cosmic microwave background radiation, and Saul Perlmutter, who led the way in discovering that the expansion of the universe is accelerating as a consequence of mysterious dark energy.



Like all great science books that return to territory that has often been explored before, "After the Beginning: A Cosmic Journey Through Space and Time" displays the essential properties of new revelations and fresh surprises.