HAFAR AL BATIN, SAUDI ARABIA, MARCH 17 -- Daylight was fading on Feb. 25, the second day of ground combat in the Persian Gulf War, when 66 U.S. Army Blackhawk helicopters raced deep into Iraq, skimming only 10 feet above the desert floor at 165 mph.

When Highway 8 loomed ahead, the pilots flared their choppers to a standstill and more than 1,000 soldiers from the 101st Airborne Division -- The Screaming Eagles -- leaped into the rain and mud.

While his troops set up their mortars and TOW anti-tank missiles to begin attacking military convoys on the highway, the brigade commander radioed back to his division command post, "The Screaming Eagles have landed in the Euphrates Valley."

Two days later, on the afternoon of Feb. 27, as more than 1,500 allied tanks crashed through Iraq's Republican Guard units in southeastern Iraq, the commander of the U.S. Army's 1st Armored Division radioed to his deputy riding with the forward troops. "Understand we are engaging the Medina division?" the commander inquired, referring to one of the Republican Guard's top armored forces.

"Negative, sir," came the reply, according to officers listening to the radio exchange. "We are destroying the Medina division."

Those two episodes -- the severing of the main highway route from the Iraqi capital of Baghdad to the southern stronghold at Basra, and the methodical obliteration of Iraq's best fighters -- were the critical junctures in what the army has begun to call "the Left Hook," a haymaker punch by 270,000 American, British and French soldiers sweeping around the western flank that routed the Iraqi army of occupation and ended the war in 100 hours of ground fighting.

The colossal, high-speed armored attack -- mounted by the largest invasion force since U.S., British and Canadian forces landed at Normandy in 1944 -- capped four months of intense planning and weeks of even more intense training that ultimately blended secrecy, deception, anxiety, disagreement and determination into victory.

This account, drawn from extensive interviews with more than a dozen senior U.S. generals in Iraq, Kuwait and Saudi Arabia, describes how it happened. Planning the Attack

In September, as the first wave of U.S. ground forces finished deploying to Saudi Arabia, military planners pondered the unpleasant prospect of penetrating front-line defenses in Kuwait, countering an Iraqi flanking counterattack and then destroying the Republican Guard, which was seen as the paramount military force facing allied ground troops.

Among several contemplated plans was an attack that first would drive into western Kuwait -- bypassing the country's more fortified southwest -- then stop short of the Guard in southern Iraq. The allies would then "hope to hell they attacked us" so American air power and artillery could destroy the Iraqis without allied ground troops having to attack prepared defenses, according to Brig. Gen. Steven L. Arnold, the army's chief operations officer in Riyadh.

But Baghdad kept adding forces and fortifications in western Kuwait. Planners of the U.S. Army's XVIII Airborne Corps warned that any attack would require three or four more divisions in a flanking move farther west. "You've got to come around them," urged Lt. Gen. Gary Luck, the corps commander.

Gen. H. Norman Schwarzkopf, commander of the U.S. forces, needed no convincing. In a meeting with his generals in October, Schwarzkopf provided the rough outlines of his strategy, vowing to skirt the enemy's strengths and "go deep" to hit the Iraqis from the flanks and rear. Maj. Gen. J.H. Binford Peay II, commander of the 101st Airborne, turned to his friend and fellow commander, Maj. Gen. Barry R. McCaffrey of the 24th Mechanized Infantry Division, and nodded. "That's it," Peay said, and the massive "left hook" was born.

After much debate, Schwarzkopf himself finally chose the western boundary of the attack, drawing a line that ran roughly from the Iraqi town of Samawah to Rafha in north central Saudi Arabia. Two key objectives were identified early: the severing of Highway 8 and the occupation of the logistics base near Nasiriyah, code-named Orange, where any Iraqi reinforcement or escape efforts had to pass a choke point between Hawr al Malih lake on the north and treacherous dunes to the south.

Details of the plan changed incessantly until virtually the hour of attack. Planners drafted eight or 10 "branches and sequels," contingencies that provided guidance if, for example, the Republican Guard tried to escape to the west or counterattacked VII Corps, the heavily armored outfit chosen to join the XVIII Corps in the attack.

But the basic precepts remained fixed: Cut off the Iraqi occupiers with the mobile XVIII Corps and destroy them with the VII Corps. The initial attacks would come on the wings of the allied line -- the French and the U.S. 82nd Airborne in the west, the U.S. Marines and Arab forces in the east -- to gauge Iraqi reaction.

No one believed it would be easy. Luck, the XVIII Corps commander, envisioned Marine casualties of 10 to 20 percent. The 24th Division's McCaffrey, who had been wounded three times in Vietnam, estimated that his unit of 25,000 would suffer 500 to 2,000 killed and wounded.

For the VII Corps, which for nearly half a century had been garrisoned in what was West Germany as a defensive force, the prospect of attacking an endless, open desert required a quick rethinking of warfare. Lt. Gen. Fred Franks, its commander, began to consider the desert as a sea that demanded the same quick maneuvering that characterized naval warfare. Eager to encourage that concept, some of Franks's young cavalry officers waited until he was in a small van one day and then began to gently rock the vehicle, as though it were a ship at berth, while singing, "Anchors Aweigh." Matching Forces to the Task

As the plans took shape, so did the force. The first vanguard of XVIII Corps, the 2nd Armored Cavalry Regiment, reached Saudi Arabia in early December. Yet the deployment from Germany for the rest of the force was agonizingly slow, hampered by foul weather, dock strikes and the sheer inertia of loading hundreds of 65-ton tanks onto rail cars and then ships.

Normally 70,000-strong in Germany, the corps would double in size as the Army attached other units to it. Eventually VII Corps would ship 36,000 vehicles and 600 aircraft to the war zone, complementing the 23,000 vehicles and 1,000 aircraft already amassed by XVIII Corps.

Colossal logistics bases mushroomed in the Saudi desert, including one ammunition dump near King Khalid Military City that covered 40 square miles. Lt. Gen. Gus Pagonis, the army's chief logistician, supervised construction of two bases while pressing Schwarzkopf to permit construction of two more farther to the west. But the commander resisted, fearful that the buildup would alert the Iraqis to the imminent shift of both corps from their temporary bases in eastern Saudi Arabia to staging areas out west. Construction of the western bases would not start until the air war did in January, when Iraqi intelligence-gathering capabilities would be greatly reduced.

Another massive desert construction job was the building of an exact replica of Iraqi fortifications -- berms, minefields, ditches and barbed wire. The U.S. 1st Infantry Division, which had been assigned responsibility for breaching these defenses, conducted a full dress rehearsal, assaulting the replica with the entire British 1st Armored Division passing through the cleared lanes.

The British division originally had been attached to U.S. Marines in the east but was assigned to VII Corps after London insisted on participating in the main attack, according to a senior U.S. general.

When the bombing began Jan. 17, the 3 1/2 divisions of XVIII Corps began a massive, top-secret migration to the west, covering 500 miles in 12 days. To delude the Iraqis, the corps left a 100-man "deception cell" in eastern Saudi Arabia, where soldiers erected inflatable tanks and broadcast the kind of radio traffic and other electronic signals typically emitted from a corps headquarters.

Impatient to attack, convinced that many of the local Bedouins were actually Iraqi agents and worried that the repositioning of some Iraqi troops meant the American ruse was not working, XVIII Corps leaders urged Schwarzkopf to accelerate his timetable. But the commander was not about to be rushed. Starting the Clock

On Feb. 9, Defense Secretary Richard B. Cheney and Gen. Colin L. Powell, chairman of the Joint Chiefs of Staff, met in Riyadh with Schwarzkopf and some of his senior leaders. Maj. Gen. Ronald H. Griffith, the 1st Armored commander, told the assembled officials that his troops were "highly motivated, tough, disciplined soldiers who are ready to fight." But Griffith also noted four concerns: a serious shortage of spare parts that would leave him with less than half of his allotted supply when the war began; a shortage of chemical protection garments, which Schwarzkopf rectified; uncertainty over whether combat troops would outrun their fuel supplies, and a desire to have larger stocks of improved ammunition.

After Cheney and Powell left, Schwarzkopf gathered his generals and told them, "The secretary and chairman are hoping to recommend to the president on Monday that we launch a ground attack during a window of time between the 21st and 25th."

On Feb. 14, Schwarzkopf started the clock running at G (for ground assault) minus 7 days. Two days later, VII Corps made its move to the west, driving across the desert in precisely the formation it would use in the attack, then wheeling 90 degrees into position northeast of Hafar al Batin.

The armada was so colossal that it took more than an hour to fly across it in a helicopter. The corps left behind its deception cell, with phony communications transmitters and a device that feigned Hawk antiaircraft missile signals.

Last-minute efforts to negotiate an Iraqi withdrawal from Kuwait put the ground war countdown on hold for three days, until Feb. 24, giving commanders time to fine-tune their intelligence-gathering.

Special forces teams, each with six commandos, were flown by helicopter beyond the VII Corps sector. Four went north of the Euphrates River while one went west of the French zone to watch for Iraqi reinforcements being rushed into the theater. Two teams were brought back quickly after being spotted.

In addition, XVIII Corps put about 15 of its own long-range surveillance detachments into the battle zone, where they burrowed into the desert to watch and report, and VII Corps took similar actions, including use of a secret helicopter detachment known as Task Force 160, to scout the Iraqi terrain.

As G-Day grew closer, the intelligence got better. At the hour of attack, division commanders had U-2 spy plane photos of their sectors that were less than 36 hours old and showed the position of virtually every Iraqi vehicle.

What the analysts were unable to tell the army commanders was whether the Iraqis would be able to launch an effective armored counterattack and whether chemical weapons would be used to "slime" the attackers, in GI vernacular. As several hundred thousand soldiers slipped into their charcoal-lined chemical protective suits early on Feb. 24, the prospect of a quick, low-casualty war seemed ludicrous, at least to the troops. To the Euphrates

As planned, the attack began at 4 a.m. on Feb. 24. Not planned was the ease with which the Marines sliced into Kuwait in the east and the 101st Airborne leaped out in the west, where 400 helicopters set up a logistics base at Objective Cobra, a 53-minute flight to the north.

Although the French were slower in getting to their objective, dubbed Rochambeau, than some American officers had hoped, Luck felt confident enough to ask permission to launch the U.S. 24th Infantry far earlier than the scheduled departure of 6 a.m. on Feb. 25. The division -- in concert with an accelerated XVIII Corps attack -- crashed into Iraq at 3 p.m. on Feb. 24 and never looked back.

Across the battlefield, Iraqi conscripts and reservists surrendered by the thousands, chanting, "M-R-E" -- for meals ready to eat, the GI field rations -- and flashing chipper victory signs. In some cases, soldiers from the 24th threw them some food, collected their weapons in a pile, ran over the pile with a tank and then pointed them south before racing toward the Euphrates.

At dusk on Feb. 25 -- about the same time the 101st was cutting Highway 8 farther to the west, the 24th Division roared into the river valley near Nasiriyah "to the absolute shock and fear of everyone there," McCaffrey later recounted. An Iraqi commando regiment near Talil airfield, which had been badly battered by the Air Force, fought for four hours until being overrun.

Racing through Objective Gold, a large logistics center between Talil on the west and Jalibah airfield on the east, the 24th Division found 1,700 bunkers full of munitions, weapons, petroleum and other war stocks. Striking at both Talil and Jalibah, U.S. tanks raced down the runways shooting 25 airplanes that the Air Force had missed, including sophisticated MiG-29s.

Massing enough artillery to put 24 tons of high explosives on one target simultaneously, the division -- like the left hook it was leading -- seemed to gather momentum as the attack matured. The tanks turned east and charged, following Highway 8, Highway 1, railroad tracks and power lines. M-1A1 tanks clattered down the eight lanes of Highway 8 at 40 mph, shooting Iraqi tanks off heavy-equipment trailers trying to haul them to safety. Bradley Fighting Vehicles shattered truck after truck with 25mm cannon fire, as Iraqi civilians and soldiers alike ran into the surrounding marshes.

When the attackers drew closer to Basra, the Hammurabi armored division of the Republican Guard appeared about 20 miles west of the city. Following the battle from his corps command post far to the south, Luck figured that the time had come for the Iraqis to unveil their most controversial weapon: chemical agents. Turning to his operations officer, Col. Frank Akers, Luck said in his soft drawl, "Probably going to get chemed on this one, Frank."

It didn't happen. At least six Hammurabi battalions were destroyed as the Americans fired thousands of artillery rounds and rockets. At 3:30 a.m. on Feb. 28, the Iraqi division broke and fled, "streaming off into the dark," as McCaffrey later put it. 'Bobby Knight Press'

In VII Corps, Franks had an image in mind: He wanted to keep his five divisions "bunched in a big fist." A corps commander's job, Franks believed, was to get the right forces to the right spot at the right time. It was then the soldiers' job to fight.

Led by cavalry scouts in helicopters 12 miles in front of the invading army, the corps moved in a steel wedge 60 miles wide and 120 miles long, with hundreds of trucks carrying the 3 million gallons of fuel needed every day to keep the force moving.

As the 1st Armored Division, forming the corps' left flank, overran a large Iraqi logistics base at Busyyah, intercepted Iraqi communications revealed that the Iraqis hoped to pull their army out of Kuwait behind a screen of Republican Guard units forming a protective wall above the northwest corner of Kuwait.

Schwarzkopf called Franks's operations officer. "G-3, here's a message: Keep pressing, keep pushing. We want the Bobby Knight press," the commander urged, invoking the tempestuous Indiana University basketball coach.

As with the 24th Division farther north, the massed power and speed of the VII Corps' armor smashed everything in its path. Across the front, Iraqi soldiers were caught by surprise, in some cases having removed the batteries from their vehicles to cook dinner and light their bunkers.

In the rain, fog and sandstorm that blew into the defenders' faces during much of the ground war, the sights of the American tanks and Bradleys that use thermal sensors permitted them to spot and destroy targets such as the vaunted, Soviet-supplied T-72 tank -- which appeared as a rich, claret-colored mass in the gun's eyepiece -- more than two miles away when unaided visibility was only a few hundred yards.

When the weather was fair, the sky was "bumper-to-bumper airplanes," as one commander put it, with Air Force jets and attack helicopters destroying hundreds of vehicles. One intelligence officer with the 2nd Armored Cavalry kept a roster of targets which he checked off like a grocery list, as artillery or aircraft methodically demolished them. "Everything worked," Franks would later comment.

On the night of Feb. 26, Franks massed the big fist of his corps for the follow-through on the Army's left hook. After several sharp fights involving cavalry troops, the corps' three heaviest divisions -- the 1st and 3rd Armored and the 1st Infantry -- mowed down the remnants of more than a dozen Iraqi divisions, including several Republican Guard units.

On Feb. 28, by U.S. presidential decree, the carnage ended. Although fuel had been critically short at one point -- a battalion of the 1st Armored Division was down to an hour's supply before an emergency truck convoy pushed through -- the corps used only 10 to 15 percent of the 70,000 tons of ammunition it had in stock.

Veteran sergeants interviewed in five divisions last week said U.S. troops, though almost uniformly green, showed good discipline with their weapons. "Because not many of us got killed, it never got to the point where there were scores to settle," one Vietnam veteran added.

To the north, one final battle played out after the cease-fire. At 1:30 a.m on March 1, two soldiers reported Iraqi vehicles moving north through the huge Rumaila oil field. Shortly before dawn, Iraqi soldiers reportedly opened fire in an effort to clear a path toward a causeway across the Euphrates. At first light, pilots from the 24th Infantry sighted 700 wheeled vehicles and 300 armored vehicles heading for the river.

A Cobra helicopter gunship firing TOW missiles blocked the causeway by knocking out the lead vehicle. Then a two-battalion task force swept into the refinery area from the south, split into two columns and ripped up the spine of the fleeing Iraqi motorcade.

For mile after mile, the attacks left a pyre of burning tanks, personnel carriers and trucks. U.S. soldiers later noticed thousands of footprints in the mud where fleeing Iraqis, for reasons unknown, had pulled off their boots and scampered into the reeds to hide. 'I Feel Good'

As the impact of their victory hit home, Army units responded in different ways. The 2nd Brigade of the 1st Armored Division, which had destroyed a portion of the Republican Guard's Medina division, stopped abruptly at 8 a.m. when the cease-fire command crackled over the radio. Soldiers opened the hatches of their tanks and Bradleys, emerging with big grins and newly unfurled American flags.

A psychological operations unit working with the brigade unsuccessfully tried to find a recording of Lee Greenwood's "Proud To Be an American" to play over its loudspeakers. Failing that, the unit picked another tape, a Vietnam-vintage hit that was soon blaring across the desert: James Brown's soul classic, "I Feel Good."