"REVOLUTIONS" in warfare are one of the favorite topics of military writers. Four have been promised this century, each connected with a weapon which seemed destined to destroy certainties on which generals and admirals -- and statemen -- had rested their calculations since the harnessing of steam in the 1830s. The first was the submarine revolution, which threatened to make surface fleets obsolete and starve nations dependent upon maritime commerce. The second was the tank, whose prophets, the Englishmen Basil Liddell Hart and Major General J.F.C. Fuller, believed would abolish the old mass armies which had dominated battlefields since Napoleon. The third was the long-range bomber, hailed by the Italian airman, Douhet, as the weapon which would do away with armies and navies altogether. The fourth was the atomic bomb, which idealists hoped really would at last make warfare between great states impossible.

Military people, like the rest of mankind, have, however, a way of adapting to circumstances. The four weapon revolutions are with us still, more or less uncomfortably subsumed within operational doctrine, and interfering scarcely at all with the traditional practice of warfare which, since 1945, has brought the deaths of at least 6 million people in small conflicts around the globe. And we are still confronted with the specter of a large conflict, between the superpowers, which the revolutionary weapons will serve to prosecute, if nuclear power fails to deter its outbreak.

New books on new weapons can scarcely, therefore, arouse the hope that war is on the way out, or even the thrill of purely technical interest in a new human achievement which belonged to a less fraught age. Yet both these books are, in fact, of great interest, and not without a crumb of comfort for those who cling to their optimism. David Baker, a space expert, provides a history of space weapons and a catalogue of work currently in progress. The danger that he perceives, much talked of in popular science publications but little documented, is of the Soviets developing weapons which will attack and destroy America's constellation of surveillance and communication satellites which orbit in lower space. The motive for doing so would be to deprive the president of the eyes with which he can foretell Soviet hostile activity and the voice with which he would command American countermeasures. Laser and high-energy particle beam emitters are the system on which most work is being done; but cruder metallic missiles, fired from short ranges, are also in the inventory and would have the same effect could the satellites carrying them be maneuvered into the correct orbit.

Baker confronts the danger foursquare, but believes that work being done by the American defense industry is keeping pace with the threat the Russians offer. He even foresees a moment in the 1990s when America may be able to threaten Russia's land-based missiles with destruction by laser from space the moment they emerge from their silos and thus a situation in which intercontinental attack ceases to be a danger to the United States.

James Canan works in a less futuristic style, and from a more authoritative data base: He is Business Week's Pentagon correspondent. And an extremely good one, too, by all the evidence deployed here. His sources are excellent and he uses them with a precision and gift for quotation which is the mark of the high-quality journalist. Indeed, the only misleading thing apparent about his book is its title, which might better be exchanged with Baker's. Canan is concerned to tell what is most up-to-the-minute about the whole American -- and Soviet -- armory, whether deployed in the air, on the ground or on and under the sea, as well as in space. Thus he devotes chapters to the coming generation of fire-and-for-get battlefield weapons, which threaten the tank with extinction, to the next generation of fighter aircraft, and the menace they face from missiles which can outturn them while remaining their hunters, and to lasers and high-energy particle beams (he is more of a skeptic than Baker, and more critical of the fears expresed by General George Keegan, the former U.S. Air Force chief of intelligence, who contributes a foreword to Baker's book). His two best chapters are on the MX missile and the submarine. The former he makes interesting because he puts into context the politics of the missile, whose slow progress towards emplacement he represents as chiefly the result of President Carter's desire to use the MX as a bargaining chip in the SALT talks. The latter, the most arresting section of the book, achieves an uncanny level of fascination because of the quantity of fresh information he brings together and the high quality of his explanation. It is also, of course, a key element in his expose, because it is upon the ballistic missile submarine that America's second-strike capability ultimately depends.

Canan is not optimistic about the future. But neither is he alarmist. The picture he reveals is of a continuing and mutual terrorizing through new technology as first one side and then the other finds an edge round the corner of whatever "revolutionary" weapon it is that its antagonist produced last. For him there are no revolutionary weapons. In one of his neatest pieces of quotation, he cites a Defense Department spokesman who confesses that "attack and defense always work together," an admission which promises that the century will draw to a close much along the path that, militarily, it has followed these last 25 years. For those who look not for the end, then perhaps for some pause in the arms race, the only hope lies in the budget-defeating costs which new weapons now lay upon productive populations wherever they live. The point really does seem to be approaching when man will no longer be able to afford the things which he is clever enough to invent.