LYING IN AMBUSH for the writer of American history are all those amazing, amusing anecdotes and quaint details which, if used, would bury the story line, but which seem just too good to cast aside.

Evan S. Connell, in his new study of General George Custer's famous final fiasco, at first seems to be riding into just such an ambush. In his research, Connell has left no tome unturned -- the bibliography lists some 400 sources -- and in the writing he seems to have been unable to leave anything out: peccadilloes of the officers, their class standings at West Point, drinking habits of the Seventh Cavalry, profiles of salty scouts and individualistic Indians, a brief history of scalping, Custer's romance with wife Elizabeth and with a pretty squaw or two . . . All this comes rushing forth while the reader anticipates a glimpse of Yellow Hair Custer at his so-called "last stand."

But the difference between this author and his subject is that there is method in Connell's madness. He, unlike Custer, knows what he is doing and what the result will be. If the vainglorious general had tried this hard to understand what he was getting into with the Sioux and Cheyennes at Little Bighorn, he might have lived to see his goldilocks turn to silver, and might even have ridden in glory to the presidency -- one of his fond notions -- as certain other Indian-killers had done.

Connell is, with this plethora of colorful details and no regard for chronology, putting together not a narrative but a mosaic of circumstances and personalities, placing Custer in context -- political, military, cultural and psychological. The result is vivid and evocative. It leaves the reader astonished that such a man as Custer could ever have been worshipped as a hero. But his context is so well constructed that it is plain why he had to be. It was that kind of a country.

Connell does not set out to do a hatchet job (perhaps one should say tomahawk job) on Custer's reputation, but the facts speak for themselves. It is quite clear that Custer died for his own sins as well as ours. His included vanity, arrogance, fervid racism, stupidity and cupidity, love of killing, a casual disregard for the lives of his men, and plain silliness.

The only good soldierly qualities Custer seems to have had were endurance and courage -- perhaps too much courage. Custer wrote breathlessly about how brave he was, and, in phrases that would embarrass even Mars, about the glory of war. During the Civil War, says Connell, Custer lost more men than any other commander.

This handsome, flamboyant, cold-eyed cavalier may have become a romantic idol and a national martyr, but he was held in contempt by many of his officers and men. The name he fancied most was "Son of the Morning Star," bestowed upon him after he massacred Black Kettle's village by the light of Venus. His men, whom he punished for minor infractions by ridicule, lashing and branding, preferred such names as Hard Ass, Iron Butt, and Ringlets. The desertion rate from his western units was as high as 52 percent.

As for the officers, hear this typical exchange, between General Alfred Terry and an officer who did not want his unit attached to Custer's, before that final battle:

"'You do not seem to have confidence in Custer,' said Terry.

"'None in the world,' said Brisbin."

Connell, a novelist by trade, leaves the reader haunted by after-images, absurd, poignant, pathetic, and horribly brutal: The stupefying tedium and disgusting rations in remote, dusty, wind-scoured army outposts. The seething antagonism among Custer and his subordinates Reno and Benteen. White soldiers robbing Indian graves and mutilating wounded squaws for fleshly souvenirs. Custer's column, accompanied by journalists, its full military band playing Gary Owen, charging a sleeping Cheyenne village early on a frigid morning. Crazy Horse as a brooding, aloof young warrior. Surrounded cavalrymen at Little Bighorn bawling in terror, shooting themselves and each other. A thirst- tortured, wounded soldier drinking blood from a vein of his dead horse. Corroded ammunition jamming in faulty rifles. Crow Indian army scouts sitting on the ground rocking, weeping and chanting after the first report of the Seventh's annihilation. Troopers' bodies bristling with so many arrows they look like hedgehogs. The discovery of Custer's obliterated force: hills strewn with bloated, pink, stripped, mutilated corpses and dead horses. Eyeballs and brains extracted and laid out on rocks, hearts impaled on poles . . .

Connell understands that the truth of a conflict is best perceived, as in Rashomon, from all sides. He shows everything and everybody from every angle. Court-martial transcripts speak, and so does Black Elk, who was a youth at Little Bighorn. Sitting Bull, years later as a tame Indian, sums it up: "They tell me I murdered Custer. It is a lie . . . He was a fool and rode to his death." Connell, knowing he is examining a tarnished idol, comments upon all this with a droll, mocking humor.

This is a vast mural of finely executed details. And it is, after all, the omission of such gritty, pungent, human details that makes standard histories so notoriously dull. This one is never dull.