The Theory of Almost Everything: The Standard Model, the Unsung Triumph of Modern Physics , Robert Oerter , Pi Press, New York, 2006. $24.95 (327 pp.). ISBN 0-13-236678-9

The standard model, like the Roman god Janus, presents two faces to the world. To physicists, it is like Jacqueline Kennedy, chic and beautiful. But to the general public, it is like Rodney Dangerfield: It gets little respect. Robert Oerter, a physics professor at George Mason University in Virginia, has set out to change that popular misconception. In *The Theory of Almost Everything: The Standard Model, the Unsung Triumph of Modern Physics*, he attempts to give the standard model the respect it deserves. Does he succeed? Keep reading.

The task Oerter has undertaken is difficult because the standard model is not as sexy as the physics of black holes, string theory, extra dimensions, dark energy, dark matter, inflation, and so forth; and most casual readers have only a limited familiarity with many of the ideas that constitute the model. Physicists represent the standard model very simply by the gauge theories * SU * (3) × * SU *(2) × *U*(1). The group * SU * (3) signifies the gauge theory of eight color gluons coupled to quarks and to each other. The group * SU *(2) × *U*(1) is the electroweak theory, which unifies the weak and electromagnetic interactions and includes three massive gauge bosons in addition to the massless photon. One test then is to explain what those symbols mean to an audience that has not heard of most of the concepts. Thus Oerter describes what quarks, gluons, and gauge bosons are. That, however, is the easy part. The real challenge is that the standard model is a relativistic quantum field theory, which means that truly understanding it requires knowledge of relativity, quantum mechanics, fields in general, and quantum fields in particular. But there’s more: To comprehend how relativity modifies Newtonian physics, one needs to understand Isaac Newton’s *Principia*, which is also necessary to see how the new ideas are engendered by quantum mechanics. Understanding quantum fields requires knowing what a classical field is, and the best example is the electromagnetic field, so Oerter presents the contributions of James Clerk Maxwell.

The author undertakes all of these endeavors with élan. His style is entertaining and involves numerous simple and sometimes whimsical examples. For instance, in presenting time dilation, Oerter imagines a taxi trip to the airport in a world where the speed of light is only 30 mph. Assuming that the airport is 15 miles away and the cab travels 29 mph, the traveler must leave well over a half hour early but will arrive at the airport having aged only 10 minutes. To help readers grasp the idea of how a particle at a distance from a source can “sense” a classical field, the author introduces a homeowner whose neighbors are having a barbecue; the homeowner knows by the aroma that something is happening even if he or she is not invited. To explain the principle of least action, the author imagines a lifeguard who must save a floundering swimmer in the ocean. The path of least time does not involve a simple straight-line path but rather comprises two different straight-line paths—one on land, one in the water. I could continue, but you get the idea. The entire book is filled with similar examples, which are necessary to entice readers who have little knowledge of the standard model, or even of physics in general.

Of course, some of the arguments work better than others. Although Oerter uses an entire chapter to explain Feynman diagrams, I doubt if most readers will comprehend the meaning of the simple pictorial representations of complex underlying mathematical calculations, especially those diagrams with multiple loops. Also, it is hard to imagine that the concepts of colored gluons, Bell’s theorem, and the Copenhagen interpretation of the wavefunction—all of which are discussed in the book—can really be understood by the casual reader.

Despite those minor reservations, I had fun with this book because it presents so many new and clever ways to explain basic physics to nonphysicists. What is not so clear to me is whether such readers can ever really hope to understand the many concepts involved in the standard model. In fact, I was struck by the huge number of crucial ideas in the book, such as quantum theory, relativity, quarks, and gluons, that practicing physicists must assimilate. Many of those concepts are nonintuitive. In my case, much of the comfort level was reached only after considerable repetition and detailed study. The casual reader has only one shot with Oerter’s book. Nevertheless, the book gave me a lot of new ideas about how to answer friends who ask me what I do. Come to think of it, perhaps a professional physicist is not the best reviewer for Oerter’s book. Maybe it should be reviewed by someone who has little or no knowledge of the field. Now that could be interesting.

I should also point out that in the final two chapters, the author does go beyond the standard model to consider the sort of ideas many popular books embrace—for example, dark matter, dark energy, inflation, grand unification, extra dimensions, the matter– antimatter asymmetry of the universe, supersymmetry, and string theory. None of those concepts are covered in depth in the two chapters; rather, they serve as a hook for the reader who is nibbling around the edge of standard model physics.

Reading *The Theory of Almost Everything* was overall a very satisfying experience, and I will enthusiastically recommend it to friends who are interested in understanding the essence of contemporary particle physics. Oerter is to be commended for successfully pulling off a challenging project, one that we physicists hope can possibly change this Rodney Dangerfield of theories into, if not a beautiful Jackie Kennedy, at least a model that gets more respect.

**Barry Holstein** is a professor in the physics department at the University of Massachusetts at Amherst. He is a particle and nuclear theorist, and in his 35 years at the university, he has taught the theory of almost everything.