ALBUQUERQUE, N.M. -- One November day in 2004, in 30 minutes of close combat, Marine Pfc. Christopher Adlesperger, a soft-spoken, religious young man who loved poetry and art, attacked an enemy stronghold in Fallujah, Iraq, and killed at least 11 insurgents.

He killed them with his M-16 and with his grenade launcher.

He killed insurgents who were heavily armed and who had just killed his close friend Lance Cpl. Erick Hodges.

He protected two wounded squad members from attack and saved innumerable Marines.

When it was over, Pfc. Aldesperger's face had been bloodied by shrapnel and he had bullet holes in the sleeve and collar of his uniform. He refused to be evacuated until Cpl. Hodges' body was recovered.

"It was a tremendous bit of fighting," said Col. Patrick Malay, the battalion commander. "He was a quiet kid, but he was remarkable."

For his bravery, Pfc. Aldesperger is among a handful of Marines who have been nominated for the Medal of Honor in Iraq.

A nomination does not ensure that an award will be made. No Marine has been awarded the Medal of Honor for combat occurring since the Vietnam War.

The nation's highest recognition of bravery is reserved for those who have shown conspicuous gallantry above and beyond the call of duty. In fact, two-thirds of the Medals of Honor awarded to Marines since the beginning of World War II have been posthumous.

If an award is made to Pfc. Aldesperger, his, too, will be posthumous.

A month after the firefight for which he was nominated, Pfc. Aldesperger led Marines in storming another building where insurgents were hiding. He was shot in the heart and died instantly.

Only after his death did family members learn of his bravery. At first they were shocked -- this was the same person who had once cringed at the thought of shooting birds on a hunting trip. Then they recognized in the details of the firefight the determined youth they knew and loved.

"That was Chris. Whatever he did, he always went in with the idea that nobody was going to beat him, nobody," said Dennis Adlesperger, 53, his uncle.

Centuries of warfare have not entirely answered the question of why some fighters, in times of maximum chaos and danger, act in a heroic fashion, putting concern for their own lives in abeyance.

Much of the Marine philosophy about bravery can be found in the classic study "The Anatomy of Courage," published in 1945 by Lord Moran, a British physician who served at the front during World War I.

Dr. Moran's thesis is that men fight not just for survival or patriotism but in response to strong leadership -- and because they have grown to identify with their group so tightly that any threat to the group is seen as intolerable.

Courage, Dr. Moran suggests, is a moral quality that comes from an unwillingness to quit. Fear, he says, is a critical part of it. Without fear, he argues, there is no courage; fear provides the energy, the resolve.

In boot camp in San Diego, one of Christopher Adlesperger's drill instructors instilled the reality of combat when he scanned more than 100 recruits sitting attentively on the exercise field and picked 10 at random to stand up.

"When your company goes to Iraq, this is the number of Marines who won't be coming home alive," the DI barked.

He ordered 10 more to stand. "And this is how many more will die if you don't start listening to me."

Normally self-confident, Pfc. Aldesperger sounded shaken when he told his mother about the lecture.

"Chris said the DI scared him, but it helped him realize what Iraq was going to be like, that he was going to have to learn to protect his Marines," said Annette Griego, 41, Pfc. Aldesperger's mother.

Looking back, family members realized Pfc. Aldesperger was a nearly perfect candidate to become a Marine. He loved family and structure, even though he did not always have that. His mother and father were unmarried when he was born, and their hasty marriage soon dissolved.

Pfc. Aldesperger grew up in Albuquerque mostly with his father, Gary, a pipe fitter and recovering alcoholic with a checkered employment history. He also lived for several years with his paternal grandmother, spent some summers with his mother and finished high school at the home of his mother's parents. He accommodated all of the moves.

"He was always trying to please people; he was starved for affection," Pfc. Aldesperger's uncle Dennis said.

He was close to his aunts and uncles and cousins and particularly to his grandfather, Edwin Adlesperger, a retired oil-company sales representative. The two enjoyed camping and fishing, and Ed gave his grandson a used Ford Contour.

Ed Adlesperger died unexpectedly in August 2003 at age 73. Chris Adlesperger, who had enrolled at the University of New Mexico, quit after a few weeks. Family members believe that if his grandfather hadn't died, he would not have enlisted.

"He was grieving his grandfather, looking for something he lost, some structure," said Phillip Blackman, who had been Chris Adlesperger's tae-kwon-do coach and gave the eulogy at his funeral. Under Mr. Blackman's tutelage, Pfc. Aldesperger had become a national champion.

"He only knew one way: straight ahead," Mr. Blackman said. "There was no 'retreat' in his vocabulary."

By all accounts, Pfc. Aldesperger loved the Marine Corps. He thrived on the physical challenge and packed muscle onto his 5-foot-8, 150-pound frame. He got a tattoo, USMC, down the right side of his stomach. He formed fast friendships.

"The Marine Corps became his family, and when they went to fight, he was looking out for his brothers," said Debra McAtee, 42, whose sister is Pfc. Aldesperger's mother.

Shortly after dawn on Nov. 10, 2004, the Marines of Kilo Company in the 3rd Battalion, 5th Regiment, pushed out. The battalion had drawn one of the most dangerous sectors, the Jolan neighborhood in Fallujah's northwest corner.

Like window washers trying to clean a grime-streaked window, the Marines would sweep methodically through Fallujah, searching each house for insurgents in what they called the squeegee tactic.

For hours, they faced only minor resistance. A few more buildings and they could stop for the night.

"We had cleared buildings all day, hundreds of them, but on that 101st house, that's the one that gets you, and that's what happened," said Gunnery Sgt. Paul Starner, Pfc. Aldesperger's platoon sergeant.

Like a lot of buildings in Jolan, the structure had a wall around it. There was a courtyard in front and an outdoor stairway leading to the roof.

Pfc. Aldesperger, acting as the point man for the four-man fire team, attempted to knock down a gate. Cpl. Hodges moved forward and was immediately felled by a hail of bullets, probably from a concealed opening in the masonry wall.

As they rushed the house, Navy corpsman Alonso Rogero was hit in the stomach and Lance Cpl. Ryan Sunnerville in the leg. Grainy, shaky film of the incident shows Cpl. Sunnerville hopping on one leg, still firing his M-16. Marines and insurgents exchanged gunfire at a distance of no more than 20 feet. From inside the building, the insurgents threw grenades.

The insurgents had hoped to spring what is called a Chechen ambush. The strategy, Marines determined later, was to wound Marines attempting to enter the building. When other Marines came to help, an insurgent sniper down an alleyway was to pick off corpsmen, radio operators and officers. And when enough Marines or vehicles were gathered, the insurgents planned to fire rocket-propelled grenades.

Pfc. Aldesperger fired at the insurgent machine-gun position as he ran toward Corpsman Rogero and Cpl. Sunnerville. He helped the two up the outside stairway to the roof.

As insurgents tried to storm the stairway, Pfc. Aldesperger killed them before they could reach the roof. Shrapnel ripped into his face.

From his rooftop position, he could see insurgents peppering Cpl. Hodges' lifeless body with bullets, including two to his head. When one insurgent ran from the building to seize Cpl. Hodges' weapon, Pfc. Aldesperger killed the insurgent with a single shot.

Still, the machine-gun position inside the building had not been touched, and it was pinning down Marines gathering to assault the building from the front. With no time to consult officers, and with other Marine units engaged in firefights, Pfc. Aldesperger was left to his own initiative.

"Chris essentially took over," Col. Malay said.

Unable to penetrate the building with his M-16, Pfc. Aldesperger shifted to the grenade launcher. Standing on the roof, he blew holes in the building and then rained down gunfire on the insurgents below. They returned fire and then fled.

Pfc. Aldesperger killed four insurgents who fled into the courtyard, each with a shot to the head. By Col. Malay's estimate, Pfc. Aldesperger killed a total of 11 insurgents. The actual number may be higher.

The building had been an insurgent command-and-control center. Failure to quickly subdue it, Col. Malay concluded, could have thrown off the timetable for the Fallujah assault, which depended on speed and keeping U.S. casualties to a minimum.

Marines from other rooftops joined Pfc. Aldesperger and began preparing the wounded for evacuation. Once that was done and Cpl. Hodges' body was removed, the Marines pushed in one side of the building with an amphibious assault vehicle. Pfc. Aldesperger insisted on being the first Marine to search the building to make sure all the insurgents were dead.

On Thanksgiving weekend, with the entire company watching, Pfc. Aldesperger, who had just turned 20, was promoted to lance corporal because of his actions on Nov. 10. Sgt. Starner also started talking with Pfc. Aldesperger about attending sniper school, a prized assignment.

In early December, Central Command ordered a second round of squeegee to catch insurgents who had been overlooked or who had managed to sneak back into the city.

This time, fewer troops were assigned; some battalions had been redeployed to other cities as the U.S. military tried to decrease its Fallujah "footprint" in advance of the city being reopened to residents.

This time, Pfc. Aldesperger's battalion was assigned to sweep a different neighborhood.

"We moved across the Line of Departure, and 20 minutes later Chris was dead," Col. Malay said.

Pfc. Aldesperger had taken the lead in approaching a nondescript house. He was hit in his flak vest by multiple rounds. The impact spun him around, and one round struck his side, where there were no protective plates. He died instantly from a bullet to the heart.

Sgt. Starner and other Marines lifted Pfc. Aldesperger's body onto a Humvee. An air strike demolished the building, burying the living and dead in rubble.

Months later, when the deployment ended, the boot camp DI's prediction had proved eerily accurate. In Pfc. Aldesperger's Kilo Company, 11 Marines had been killed.