They gathered anxiously that first October morning, the 50 members of class "06-01," the first of 750 agents-in-training who will graduate from the FBI Academy this year.

In the first of many traditions they would encounter at Quantico, the recruits, still dressed in their dark civilian suits, were asked to stand and describe their backgrounds and explain why they wanted to join the FBI. For many, the amphitheater-style classroom was not a surprising destination. Thirty students -- 60 percent of the class -- had been in the military or law enforcement, traditional recruiting grounds for the FBI.

But others came from the highly educated nontraditional backgrounds the bureau has tried to emphasize.

The recruits, whom the FBI would not allow to be fully identified in this article, included Jenny, 27, a biomedical engineer with a doctoral degree in pathogenesis; Michelle, 28, a lawyer from a white-shoe Manhattan law firm who was taking a 75 percent pay cut; Alex, 32, a lawyer and college instructor from Georgia with a doctorate in forestry; and Elvis, 36, a Chinese American with degrees in chemical engineering and chemistry. There were no Arab Americans and only one black recruit.

If the FBI answered a call that many of the recruits had heard for years, it was something different for Elvis, who had left behind in Sacramento a pregnant wife, a 15-month-old daughter and an ill father who worried that his son -- who had never handled a gun -- might accidentally shoot himself. Elvis had a lucrative job in Silicon Valley and felt set for life until terrorists attacked the Pentagon and World Trade Center. "I thought, 'Man, what am I doing here? I'm making computer chips.' It all felt so heartless. I thought, 'What can I do to help?' "

On a tour of the academy their first night, the recruits had passed by a reminder of the FBI's new mandate to fight terrorism -- two 10-foot black granite towers formed in the shape of the World Trade Center and bathed in soft light. At the base sat a jagged stone from Ground Zero and a concrete piece of the Pentagon. On the ground nearby rested a blue metal fragment of the airplane that crashed in Pennsylvania.

Yet everywhere the students went in the ensuing 4 1/2 months there were also reminders of the FBI's past and the culture into which they were being initiated. The street leading into the sprawling academy is named Hoover Road. A portrait of the agency's controversial first director, J. Edgar Hoover, hangs in the reading room named after him. On the walls near the cafeteria and gym are posters of famous FBI movies. The one from "The FBI Story" is autographed by its star, Jimmy Stewart.

A few days into the course, Elvis and the other recruits received a pointed lesson that whatever their backgrounds -- science, law, computers or intelligence -- there could be no doubt about what they had signed on to do. It was an FBI tradition called "Reality Check." For the next hour and a half, Chuck Hauber, the firearms instructor, told the recruits -- by now wearing FBI-issue uniforms of blue polo shirts, khaki pants and hiking boots -- that there were to be no questions. Just listen, he said.

Hauber showed the class a collection of handguns he had removed from the academy's gun vault. The first was the partly melted remains of a .40-caliber Glock 22 that had been carried by an FBI agent who rushed into the World Trade Center.

You are volunteering to put yourself in harm's way, Hauber said. When everyone is running away from danger, you must run toward it.

The Glock was followed by a 9mm Smith & Wesson with a bullet hole through the middle. The gun belonged to a special agent who was killed with another FBI agent during a gun battle in Miami in 1986. Then a 9mm SIG Sauer that a criminal wrested away from a female agent at D.C. police headquarters in 1994. He shot her in the head.

Hauber then asked the recruits to look under the firearms manuals in front of them. Everyone who found a slip of paper with a name and age scrawled on it was to stand and read them. The 16 names read off were of agents killed in the line of duty, Hauber said, agents who once sat in this room. In those exact seats, he said. They were just like you. Don't think it can't happen to you. You need to think about it.

To reinforce the message, he played a grainy black-and-white video of a South Carolina highway trooper pulling over a car. In seconds, the video ended with the trooper being shot by the driver and screaming into a radio for help. A gurgling sound could be heard through a microphone the officer was wearing.

The trainees stared in stunned silence.

Think about this over the weekend, Hauber told the recruits. Make sure this is the job for you. If it is, I'll see you next week.

By the end of the weekend, two of the class's nine women had dropped out. One was Lisa, a 33-year-old Asian American corporate lawyer from Oregon who had dreamed of becoming an FBI agent since she was a teenager. When she arrived at Quantico, however, she quickly felt that she didn't belong.

"Until you get there, it's hard to explain," Lisa said. "It was the demands, the pressure, the lifestyle. It's much more of a military-type organization than I expected. A lot of the agents are police or military. I wasn't used to calling people 'sir' and 'ma'am.' I felt like it was going to be 18 weeks of boot camp."

Even with those feelings of doubt, Lisa stuck with it for a couple of days. After all, it had taken so long to get there. But after the firearms class, she knew she had to leave. It hit her that being an FBI agent also really meant being a cop.

'Just Don't Quit'"Orders," another ritual, sent a different but equally powerful message about the FBI and the agents who serve in it. During the first week of class, recruits had been asked to rank preferences for their first assignments among the FBI's 56 field offices. Five weeks later, at Orders, they very publicly learned their fates.

By tradition, recruits had to go to the front of the room and tell their classmates their first choice before receiving the sealed envelope with their assignments. Each one then had to open the envelope, call out where he was going, collect himself and pin his picture on a giant map of the United States.

Elvis was one of the few to get his first choice -- San Francisco. One woman said she wanted Honolulu and the class laughed. She didn't get it. Jenny asked for Atlanta but received Washington. One trainee muttered under his breath, "Boy, I didn't see that coming," as he pinned his photo on New Haven, Conn. On the map, clusters of pictures were concentrated on each coast, with 18 of the trainees headed to New York, Washington or Los Angeles. But most of the class was scattered across the country, from Anchorage to Kansas City. Every three to five years, they must be ready to pick up their families and move again.

The recruits did not complain. They were becoming part of the FBI culture, ready to serve wherever the bureau sent them. Geoffrey, a former Marine, looked at the FBI instructors, who had lined up in the back of the room to watch the ritual. "I really don't mind wherever I go as long as I can have a job and keep doing work like the people in the back," he said, opening his envelope. "And it's an honor to be here."

Besides reinforcing any lingering doubt about being at the bottom of a rigidly hierarchical system, the assignments also illustrated a cardinal precept of the training -- that agents will be responsible for enforcing a wide range of federal laws.

"Some agents may go to a two-man office in Montana or five-man office in Victorville. Some may go to WFO [Washington field office] or New York. WFO has dozens of counterterrorism squads. But if you are in a two-man office in Montana, the focus won't be on foreign intelligence," said Supervisory Special Agent Michael Esposito Jr., who oversaw class 06-01.

One day in January, the class waited in a muddy yard behind the gym for "OC Spray," remembered by just about everyone as the worst day of training.

Jenny, the biomedical engineer, stepped forward and stood ramrod straight in anticipation. The instructor raised a canister of a derivative of cayenne pepper known as oleoresin capsicum, or OC. Pepper spray. From four feet away, the instructor let loose a big burst.

Jenny choked, coughed and gagged. "Open your eyes!" the instructor screamed. "Open your eyes!"

To pass, Jenny had to open at least one eye, protect her gun from a trainee trying to grab it and force the trainee down spread-eagle onto the ground before yelling "FBI! Don't move!"

One by one, the sprayed trainees, hunched over in agony, were led away to rinse their swollen faces and red-rimmed eyes. The point of the exercise was not merely to toughen them; the instructor wanted them to understand what OC spray felt like before they used it on someone else and to know that they could survive if it's used against them.

The next day, there was "Bull in the Ring," an ordeal designed to bring the recruits face to face with the old-fashioned culture of toughness that has long been part of the FBI. The trainees who had never been in a fight would experience one now.

Wearing boxing gloves, headgear and mouth guards, they were arranged in five circles in the academy gym, according to weight. "We're classmates, pals and friends," an instructor told the trainees. "But for the next hour, we're not. Just don't quit. Do not turn your back. It's going to hurt. It's not fun. You can't duck. You have to survive. Work your way through it. Keep going."

Jenny stood in the middle of the circle, surrounded by nine other trainees. One man moved into the circle and sent his fist into Jenny's face. She took the punch and tentatively hit back. He hit her in the shoulder and kept pounding. Then he backed up and another trainee moved in and began pummeling Jenny. For two minutes, she took and threw punches.

The instructors ordered them to do it all again for another two minutes each. Afterward, they had to punch each other as hard as they could while fighting on the ground.

The "Rocky" theme song was blaring.

Elvis jabbed cautiously at Michelle, the former corporate lawyer. He was uncomfortable punching a woman, especially one who had become a good friend.

"Hit her harder," an instructor yelled.

The Art of Interrogation Inside an interview room, Michael, 36, an Atlanta computer specialist and former professional football player, casually chatted up an actor playing "Pat Taylor," an employee of a defense contractor building top-secret radar systems. It was week 12. While their instructors watched them on video monitors, the trainees were learning how to elicit confessions.

The recruits received 70 hours of instruction on what is perhaps the most critical FBI skill: the art of interviewing and interrogation. FBI agents rarely use their guns or get into street fights, but they do spend most of their time talking to people. In the most basic sense, an agent's job is to get information that can be used to solve crimes or stop terrorism.

Michael asked Taylor, suspected of stealing a blueprint to sell to a North Korean intelligence agent, about his family, job and two children. The Washington Redskins came up and Michael said he used to play football professionally, "but I'm new to the area and I'm not a Redskins fan yet."

In a room nearby, several FBI instructors groaned and laughed. Great way to build a rapport with someone from around here, they joked.

Despite the Redskins comment, Michael seemed to connect with Taylor, showing respect and learning about his life. He smoothly asked him to sign away his Miranda rights.

After leaving the room to let Taylor stew, Michael returned, removed his jacket and rolled his chair closer to Taylor. Using information gleaned from the interview, he now had to go for the confession.

"At this point, they need to move in," said the instructor, Supervisory Special Agent Christopher J. Zisi. "Invade their comfort zone. Let them smell the chili you had for lunch. They can't think straight."

Michael said: "Now, Pat, I understand you are a single father. You have a lot of responsibility and you have a lot of bills. I understand that, Pat."

Taylor tried to say something, but Michael cut him off. The trainee is supposed to show who's in control with a 10-minute monologue.

"Listen to me, Pat," Michael said. "You took the prints simply because your son needs more money. I understand that. I'm a father and I would do almost everything for my kids, I really would."

The technique is called "rationalization" and expresses sympathy with the suspect. But Michael got the confession by bluffing with a blank videotape that he says captured Pat in the act.

That's a risky move, Zisi said. If there were a video machine in the room, the suspect could have called Michael's bluff.

Under FireDuring week 17, with the end in sight, the trainees lined up to take their final firearms exam at the outdoor range. Each had to fire a gun from four positions at four distances, 150 shots in all. To pass, each trainee had to put at least 120 shots in the target. When he finished, Jason, a 25-year-old Army lieutenant planning to get married the day after graduation, had a sinking feeling. There were not as many bullet holes in the in the target as he had hoped. A somber instructor carried over his scored target. Jason had failed by one shot. Tears filled his eyes. He knew what that meant: He would not graduate with his class.

Growing up in small-town Kentucky, Jason was familiar with guns and cut from the traditional mold of an ideal FBI agent. He won a Bronze Star in combat in Iraq. He was the top scorer in the final physical fitness test. He peppered his language with "Yes, Sirs" and "Yes, Ma'ams" and described himself as a Type A personality.

Jason was immediately placed with a new class and given special instruction. If he failed the next firearms qualification test, he would be out. (He passed a month later.)

For his former classmates, there was one more firearms exercise -- FATS -- a firearms training simulation. In a darkened room, with classmates sitting behind, each trainee was called forward to face a movie screen with a video simulating a potential crime unfolding. The trainee had to decide whether to shoot. Act too quickly and an innocent person could be killed. Hesitate and it could be the trainee.

It was Elvis's turn. He had worked as hard as anyone in the class, waking at 5 a.m. to work out and lifting weights at lunchtime. He was also one of the class's most outgoing and popular trainees. His nickname was "The King."

On the video, his partner knocked at an apartment door looking for a fugitive's girlfriend. But the suspect himself opened the door. Elvis's partner pulled his gun. Lunging, the suspect took away the gun and the two men rolled on the ground, fighting for it.

Elvis, the chemical engineer who had never fired a gun before Quantico, leapt onto a table. His heart racing, he shot at the suspect, who was still on the ground tussling with his partner. The suspect's girlfriend suddenly appeared at the door. Elvis yelled for her to stay back. It happened so fast that it was hard to see where the bullets landed.

The lights came on. The instructor felt Elvis's pulse, to comic effect. Then the instructor became serious. "Did you shoot your partner?" he asked.

Elvis's face fell. "I don't think so," he said.

When the computer simulation was rerun in slow motion to track each bullet, it was clear: Elvis had missed his partner and killed the criminal with a shot to the head. His classmates cheered.

Crossing OverOn the morning of Feb. 17, parents, grandparents, spouses and children streamed into the huge FBI auditorium. It was graduation day. Class 06-01 lined up for a photograph with FBI Director Robert S. Mueller III, who swore members in as special agents.

""We are on the front lines for America," he told them. "Will you develop the source that provides the intelligence we need to disrupt a terrorist plot? We must continue to change because the terrorists certainly will."

They walked down the long glass-enclosed corridors for the last time. They crossed the grassy quad, past the granite twin towers and the piece of United Airlines Flight 93. They headed toward the gun vault, where their firearms instructor was waiting for them.

Eighteen weeks earlier, he had gone into the vault to get something to show the class: the burned Glock 22 handgun that an agent had carried into the World Trade Center. Now, he handed each of them something of their own. A brand-new Glock 22.