By Bruce Chadwick. Illustrated. 366 pp. New York: Alfred A. Knopf. $27.50.

"In learning history, nothing beats a good Hollywood film." So stated the classroom study guide to the Civil War movie "Shenandoah," made in 1965. Although the film told the story of a family in Virginia's Shenandoah Valley, it was shot in Oregon, to the outrage of many Virginians. When challenged about this location, the director declared, "There is no place that looks more like Virginia than Oregon."

For Bruce Chadwick, this comment is a metaphor for the accuracy of most of the 800 Civil War-era movies made since 1903: they bear as much resemblance to historical reality as Oregon does to Virginia. Over 600 of these films date from the silent era, mainly 1908-16, the years surrounding the 50th-anniversary commemorations of the war. With few exceptions these were short one- or two-reelers. The big exception was "The Birth of a Nation," a technical and artistic breakthrough that confirmed D. W. Griffith's reputation as one of the greatest directors of all time.

In "The Reel Civil War," Chadwick, a lecturer on history and film at Rutgers, analyzes Hollywood's treatment of the Civil War at length. He makes a strong case for "The Birth of a Nation" as the quintessential example of how movies perpetuated myths about the conflict until at least the 1960's: showing a moonlight-and-magnolia South of white-columned mansions, beautiful women, gentle men and happy slaves that was destroyed by a war in which Southern whites lost all save honor but struggled heroically to overcome postwar despoliation by carpetbaggers and their ignorant black pawns. A generation later, "Gone With the Wind" became the second great example of Hollywood's romanticized version of the South.

Most Civil War movies, Chadwick tells us, presented the South as the underdog, doomed to defeat by the greater numbers and resources of the industrial North, but making an honorable fight. Often the Confederacy appears as a victim, with the implication that the North was the aggressor. The historical reality -- that Confederates started the war by firing on Fort Sumter -- is almost never suggested.

The principal theme of many of these films is the postwar reconciliation between Northern and Southern whites, frequently sealed by a marriage (in "The Birth of a Nation," two marriages) between a bride and groom who were on opposite sides during the war. Or, in keeping with the "brothers' war" theme of numerous movies, two brothers (or a father and son) are reconciled and become part of one big happy family again. These films represent both sides as fighting courageously for what they believed was right. That the Confederacy fought for slavery and the destruction of the United States as one nation cannot be mentioned, for that would hinder reconciliation and reunion.

When slaves appear in these movies, they are either happy-go-lucky Sambos or obese Mammies, while freedmen are vicious savages or doltish dupes. "The Birth of a Nation" was the worst offender in this regard. Its portrayal of the Reconstruction Ku Klux Klan as white knights who saved the South from black beasts inspired the founding of the second Klan, a powerful force for intolerance in the 1920's.

"The Birth of a Nation" was one of the greatest box-office successes of all time, seen by 200 million people in the United States and abroad from 1915 to 1946. Chadwick scarcely exaggerates in describing it as "a blatantly racist film that egregiously slandered American blacks and helped to create a racial divide that would last for generations."

And, he adds, "the fingerprints of 'Birth of a Nation' were all over 'Gone With the Wind.' " In Atlanta a schoolgirl saw Griffith's film a dozen times and staged her own neighborhood play based on it; her name was Margaret Mitchell. Chadwick's fascinating account of the making of her novel into a movie shows that most scenes of a noble Klan and vicious free blacks were left on the cutting-room floor by the producer, David O. Selznick. But the other stereotypes of the plantation myth -- kind masters, happy slaves and victimized South -- remained in the film, and remain to this day in the minds of many whites as dominant images of the Old South and the Civil War.

One-third of "The Reel Civil War" concentrates on these two movies. Given their prominence, that seems a reasonable balance, and Chadwick's dissection of the myths they helped to foster is superb. His chapters on the early silent films and on movies about Abraham Lincoln are also outstanding. But his thesis that many films depicting Lincoln contained a subtle pro-Southern bias, because Lincoln "was the single greatest catalyst in reunion movies," seems a bit forced.

The book's final chapters on the decades since "Gone With the Wind" tend to lose focus. Television shows and miniseries receive as much attention as movies, sometimes more. Even a 1999 Broadway musical, "The Civil War," gets greater space than, for example, a genuine Civil War movie like "Friendly Persuasion," which Chadwick describes as "one of the finest films of the period" but then virtually ignores. Other post-World War II films, like "The Horse Soldiers," are discussed in only a few sentences. One of the finest films, "Red Badge of Courage," receives but two paragraphs, while "Roots," which was neither a movie nor primarily about the Civil War, gets a whole chapter. To be sure, "Roots" helped overturn the victimized-South myth, and Chadwick implies that it paved the road to "Glory," which does receive extensive treatment. One suspects, however, that "Glory" would have been made even if the "Roots" phenomenon had never occurred.

Chadwick has also allowed his thesis about the pro-Southern bias of Civil War films to lead him into a few distortions of his own. Michael Shaara's novel "The Killer Angels," on which the movie "Gettysburg" was based, was not "written from the Southern point of view." And the famous scene of Atlanta burning in "Gone With the Wind" was the result of Confederates setting fire to everything of military value when they evacuated the city, not a consequence of Yankee arson -- a mistake that Chadwick shares with perhaps 99 out of 100 viewers. Still, the reader should not let these and a few other minor errors, or the bad pun of the book's title, detract from the genuine virtues of this enlightening volume.

James M. McPherson is George Henry Davis '86 professor of history at Princeton and the author of "Battle Cry of Freedom: The Civil War Era."