This is the cost of war in Afghanistan and Iraq: the loss of so much promise and potential. More than 800 American men and women have now died in the military effort, and thousands have been wounded. American troops tend to be honorable but anonymous—working-class or poor, disproportionately black, brown or rural. If they come home, they often return to quiet lives as clock punchers. But in Tillman, the sacrifice of war suddenly bears a face of stardom. The Pentagon can try to block images of flag-draped coffins. But Tillman's death is a startling billboard of grief, a reminder that these lost soldiers—all of them, famous or not—had so much left to give.

Tillman had everything: riches, smarts, good looks. An academic All-American, he had a 3.84 grade-point average in marketing at Arizona State. He joined the service just after a honeymoon to Bora Bora with his high-school sweetheart, Marie. He and a younger brother, Kevin, slipped off to enlist in Denver, where they could avoid publicity. Kevin, who gave up a budding minor-league baseball career, remains in the Army. Pat Tillman wanted no attention, no glory, for joining the rank and file. He "didn't want to be singled out from his brothers and sisters in the military," says former Cardinals coach Dave McGinnis. Tillman apparently had made a pact with his family to stay silent about his service, a promise they have kept. They have gathered to grieve inside the comfortable family home in a leafy enclave of San Jose.

His was no simple case of patriotism; Tillman was never known as a flag-waver. His agent, Frank Bauer, told reporters he had suspected that Tillman might quit to teach or to practice law like his father, Patrick Sr., but not to join the military. Snyder, his college coach, said Tillman never used the word patriotism when he explained his plans to enlist. "He just seemed to think something had to be done." When players asked why he enlisted, he didn't want to talk about it. McGinnis says there were "reasons Pat said he had that he didn't want to divulge," and the coach respected his view and his right to make his own path. Tillman had always been different. When he joined the pros, he rode a bicycle to practice because he didn't own a car. He refused to buy a cell phone. A sports publicist at Arizona State once described him as "a surfer dude."

Growing up in San Jose, Tillman went to Leland High School. "All the girls loved him," says a former classmate, "and all the guys wanted to be him." But he was not perfect. His Spanish teacher, Carla Lucarotti, recalls that he had a mischievous streak about him. "They were all young and crazy," Lucarotti says. In high school Tillman got into a fight—defending a friend—and ended up being charged with felony assault as a juvenile. He pleaded guilty and served time on a work farm the summer before entering Arizona State. A sports reporter, Tim Layden, wrote about Tillman's candor when asked if he'd ever been arrested or gotten into trouble. "Nickel and dime stuff—he didn't have to tell me the truth," Layden wrote.

Tillman gave up a $3.6 million contract to join the harrowing world of life as an Army Ranger. The training alone is nearly intolerable: working to exhaustion—in conditions of swamps, jungles, mountains—about 20 hours a day. Rangers are sent to places where the danger is the worst. That's where Tillman was on Thursday. Dusk was falling and the new moon hadn't risen yet—the darkest time of the night for eyes still smarting from the blinding mountain sun and daytime temperatures of 105 degrees. Military officials say that Tillman's unit was ambushed in a region where Qaeda forces sneak across from Pakistan. The coalition returned fire. Two other Americans were hurt. One Afghan soldier was killed.

On a trip home in December—after serving in Iraq—Tillman made a surprise visit to his old Cardinals teammates at a game in Seattle. Again he refused to explain why he gave it all up for the harsh life of a soldier. His intensity was not unexpected. His former teammate Pete Kendall says, "The people who knew Pat, the less surprised you were." He told his pals he intended to return to football after his tour of duty. Just before he left, he thanked McGinnis for letting him come to visit. "No—thank you," said McGinnis. And then Tillman slipped out a side door, intent on avoiding attention.

Known for engaging his teammates in deep talks in the weight room, Tillman had always looked for a hurdle to jump. Bored during one off-season, he ran a marathon. Next he did a triathlon. Renowned for his toughness, Tillman seemed bulletproof. Bauer, his agent, says NFL coaches and execs would joke that if anybody was going to find Osama bin Laden, this was the guy to do it. He died trying.

With Robina Riccitiello and Karen Breslau in California, Ronald Moreau in Pakistan, Owen Matthews in Afghanistan, T. Trent Gegax in New York and Randy Collier in Arizona