Fighting the Fight : Will we ever sort out the causes of this century’s global conflicts? : THE FIRST WORLD WAR: A Complete History, <i> by Martin Gilbert (Holt: $35; 615 pp.)</i> : ON THE ORIGINS OF WAR, <i> by Donald Kagan (Doubleday: $30; 486 pp.)</i>

‘War makes rattling good history; but Peace is poor reading.” So speaks the Spirit Sinister in Thomas Hardy’s “The Dynasts.” Sinister or not, American publishers are well aware of this dictum. Popular interest in the two World Wars goes on and on. It may subtly differ from the appetite for books about the Civil War and the Vietnam War, since histories of the latter are compelled to deal with the domestic political climate of that time, while in books about the Civil War there seeps in a well-nigh unavoidable lyrical and melancholy tone, given the distance that separates Americans now from the time and the people of what was the American Iliad.

The appetite for books about the World Wars of this century may differ in kind, but not in degree.

Now here are two massive histories, by reputed professional historians, one, “The First World War,” the other, “On the Origins of War,” of which more than half deals with the origins of the two World Wars.

The second World War was the consequence of the first. Both mark the last attempt of a great European power to achieve domination over most of the continent. The Germans lost World War I, but they rose again and tried again--an enormous and dramatic chapter in the history of mankind, since it took the combined powers of the greatest of states and empires to defeat them. The Germans would have risen--indeed, they had risen--even before and without Hitler; but whether there would have been another world war without Hitler is debatable. What is not debatable is that Hitler’s compulsion to become a national leader was the result of the Germans’ humiliation after World War I. On the other hand, the Kaiser--with all of his faults, and there were many--was not a Hitler; and the barbarism of the second World War was so much worse than that of the first. Yet it was during the first that the confidence of European civilization received wounds from which it has not recovered.

Martin Gilbert is a reputable and prolific English historian, the author of more than 40 books, mostly about World War II, documentary editions and atlases (his interest in geography and his ability as an amateur cartographer are commendable and useful for this book). At the beginning of this massive volume he tells us that he had been interested in World War I for a long time; indeed, he seems to have visited many of its battlefields.

To write “A Complete History”--the perhaps unwarranted subtitle of Gilbert’s “The First World War”--is admittedly a difficult task. The war went on many fronts, starting here, stopping there, so that the chronological treatment must be interrupted often, flitting from one theater of the war to another, entanglements of the story with which Gilbert struggles, not always successfully. For the sake of readability Gilbert includes a somewhat novel element. Culled from his wide reading of all kinds of accounts and memoirs and letters, he intersperses his treatment of the military and political events with passages of personal reminiscences, including on occasion poems, for the sake of illustrating the poignancy or the details of a certain place or time. This often works, and lightens the narrative sequence, but not enough. His one-volume history does not compare in verve and style to Churchill’s one-volume abridgment of World War I, “The World Crisis,” written more than 70 years ago. Gilbert is aware that World War I was a struggle during which entire nations rushed at each other--hence the importance of describing not only armies and governments but also how the war affected the lives of everyday people away from the battlefronts: and that is not easy. All in all, “A Complete History” Gilbert’s “First World War” is not; but it is only fair to say that it is a readable attempt.

The purposes of Donald Kagan’s “On the Origins of War” are more modest. Though this is a large book, too, “On the Origins of War” is, rather, a long essay--more precisely, a combination of five essays directed to the questions: how and why war broke out, discussed and illustrated in four instances; and how a war was avoided, discussed and illustrated in the fifth.

Donald Kagan is one of our finest historians of antiquity; his “History of the Peloponnesian War” is a classic. His purposes in the present volume are not completeness or definitiveness but, through a careful discussion of the crises that led to the Peloponnesian, the second Punic, the first and the second World Wars (and finally, to the Cuban missile crisis of 1962), a suggestion of what these crises may tell us about human nature--an approach worthy of someone who is a classical historian and not a social scientist.

But there are problems here too. One of them is that, while through history continuity is as strong as is change (and Kagan knows that well), the same holds true of peace and war, with one flowing into the other. While there are definite milestones (a declaration of war, or a peace treaty) the tendencies of wartime and peacetime overlap. One example: Britain and France reluctantly declared war on Germany in September, 1939; but they were loath to begin fighting seriously, hoping for a limited kind of war against the Third Reich--a condition that Hitler recognized and from which he would profit. Something of the kind also existed in 1914, when it was the Germans whose calculations went awry: Their chancellor expected the British to fight a limited war against them, but it took some time for them to learn that they had been wrong. The other problem is that the five essays are uneven.

As may be expected, Donald Kagan’s treatment of the origins of the Peloponnesian War is the best one. His acute interest and reading in the origins of the two World Wars of the 20th Century deserve credit; but here he does not contribute much to matters that we know. At the end of the volume he found it proper to include a study of the Cuban missile crisis of 1962, as an example of a potential war that did not come about. He is critical of Kennedy’s quid-pro-quo concessions to Khrushchev; he thinks that they were not necessary. But that is not the point. His minute culling of the available documentary and memoir evidence obscures the essential issue: There was no way in which the Russians--any Russians--would risk a nuclear World War III with the United States because of Cuba in 1962 (just as the United States would not risk a war with Russia over Hungary six years earlier).

Still, the conclusion of Donald Kagan’s introduction is just and proper. No less vital than the study of war “is the art of avoiding war, and no more may the attempt to understand its origins and causes safely be neglected.”