The first question raised by this absorbing volume is where to put it on your shelves. The central character, Victor Jakob, is a fiction, or at least a composite, but everything else is historical--the work of a professional historian of science at Johns Hopkins. If this is a novel, it is a novel with nearly 50 pages of footnotes referring to various historic sources. If it is a history, it is one whose hero never actually existed.

But whatever you may choose to call it, Russell McCormmach's "Night Thoughts of a Classical Physicist" is a very readable way to learn about one of the key developments in the history of science: the transition from a Newtonian universe to one explained by the theories of relativity, indeterminacy and quantum mechanics. At the same time, it offers a cogent explanation of why world leadership in physics passed from Germany to the United States between the First and Second World Wars.

Victor Jakob is an undistinguished lecturer in physics at a provincial German university during the closing months of World War I. Born in that revolutionary year, 1848, he is now in his last active months as a physicist--a slightly baffled remnant of a dead world. He is a classicist not only in the kind of science he learned and prefers to teach but in all his tastes: the music of Bach, the writings of Goethe, the culture of ancient Greece. He reads Greek for recreation, a luxury unimaginable to most physicists of later generations, who are a much more highly specialized breed.

Both in the world at large and the small world of physics, Jakob is not very happy with the trends he observes. Despite the optimism of many colleagues and associates, and the patriotic slogans he hears at mandatory public meetings, he knows that Germany will lose the war, its dominant position in Europe and its leadership in world science. In physics, he is reconciled to the theoretical demolition of the mechanistic Newtonian universe (which happened during his career, though he had no part in it), and he is interested in the new theory of relativity, if only because it seems to allow some kind of accommodation for his pet (and unfashionable) concept of the "world-ether." He never had much of a taste for abstract mathematics and wishes there were not quite so much of it in the new quantum theory.

At the beginning of his career, physics presented an intelligible if complex picture of a world that ran like an enormous Swiss watch. Jakob used to think of physics--the entire system of theoretical physics, which he teaches--as a painting that might need a little retouching now and then but remains basically stable. Now, the world picture presented by physics is becoming more like a Picasso or a Kandinsky, with the queasy concept of indeterminacy at its core. He misses the old world picture.

Strictly speaking, of course, Newtonian physics has not been demolished; it merely has been shown to be a special case--the set of rules that applies to the small corner of reality occupied by human beings and accessible to their senses with the aid of some rudimentary experimental equipment. The phenomena that it has trouble explaining occur most notably in the macrocosmic and microcosmic worlds, which have become the territory for new exploration by physicists in this century. The tragedy of Victor Jakob's career is not that his discipline--in a sense, his world--has been demolished, but that in the future it will be crammed into the first chapter of textbooks on theoretical physics.

His other world--that of Germany throughout his career--has offered and still offers a variety of discomforts along with its special satisfactions. At the moment, these include the hard facts of war: meatless meals of thin soup at home and reports of casualties at the front. Jakob feels a twinge of sorrow for one of his colleagues, whose genius cannot ward off tragedy: "Poor devil, Planck. One son dead, the other a prisoner." But he is even more concerned for Germany as a whole:

"Don't we live in daily fear of a catastrophic breakthrough in the West now that America is sending unlimited divisions against us, Bulgaria is out of the war, Austria-Hungary is on the verge of collapse? Doesn't chaos threaten here at home? Hundreds of thousands of workers in Berlin have struck for food, peace without annexations, and democracy; the cities are starving; soldiers are deserting; the Emperor is defiled, and the monarchy is viewed as an obstacle to peace; the Crown Prince is a profligate, and his brothers are scarcely better. . . . The future of Germany doesn't depend on influence in Turkey or a piece of Belgium. It depends on character, on spirit, on idealism--on, among other things, science!"

Through the eyes of Jakob (who sees well for one who is not a genius in a field where geniuses abound), McCormmach explores deftly the factors that destroyed Germany's power in 1918 and even more disastrously a quarter-century later. Because Jakob has a name that seems Jewish (though it is not), he is specially aware of the restrictions on Jews in academic life that drove many of them into theoretical physics rather than other branches of science--a foretaste of the more virulent anti-Semitism that later sent Einstein and many others to the United States. As a government employe, he is painfully aware of the autocratic system by which appointments and promotions are made.

The book contains a marvelous portrait of the minister of culture Friedrich Althoff, who used spies, intimidation and humiliation as part of his technique for dominating his academic subjects, and whose arbitrary misuse of the talent in German universities helped to cripple the country. Also given attention are the drive to centralize scientific activity and the harnessing of scientific energies to immediate, practical applications rather than the basic research that pays much richer dividends in the long run.

Clearly, this is much more than the story of Victor Jakob's last few months at a university and his memories of a modest career. If it is classified as fiction, I suppose it is the kind of fiction that only a university press would publish in our time. But it is a book of enormous substance and fascinating implications. I recommend it highly for serious readers. And particularly for those who administer the relations between science and government in the United States.