JOHN PRYOR called home every day.

It didn't matter if rockets were exploding in the sky above him, or if the streets of Iraq ran red with blood. He always took a few minutes to let his wife, Carmela Calvo, hear his reassuring voice.

On Christmas Day, Calvo's phone went silent.

She tried to allay her fears when she read about an unidentified U.S. soldier who had been killed near Mosul. Pryor, an esteemed trauma/critical-care surgeon at the Hospital of the University of Pennsylvania, must've been busy working on the poor soldier, Calvo told herself.

She kept believing that scenario until a few military officials arrived at her Moorestown, N.J., home and delivered the gut-wrenching news: Pryor, 42, a trauma surgeon with the 1st Forward Surgical Team, had been killed by an enemy mortar round.

The mortar round had apparently been blindly fired at the Mosul Air Base and landed in a trailer where Pryor was sleeping, not long after he had returned from Christmas Mass, said his brother, Richard.

"This was not an assault or a barrage," he said. "Someone fired a single, sporadic blind shot to see what it would hit . . . and it hit my brother."

In a mere instant, Pryor's family lost a loving son, husband, brother and father of three.

And both Philadelphia and Iraq lost a widely admired doctor who treated his career as a calling and was devoted to helping people, regardless of their race, ethnicity or social status.

Pryor's humanity knew no limits, his friends and family said.

When his high-school pals in the suburbs of Albany, N.Y., were worried about cars and prom dates, Pryor was riding in ambulances and learning how to be a paramedic, his brother said.

Richard Pryor said that his brother had applied to "every medical school twice and didn't get in," but didn't give up.

He eventually got accepted to the University of New York at Buffalo, and did a fellowship at HUP, where he quickly rose through the surgical ranks to trauma-program director.

When the twin towers collapsed on Sept. 11, 2001, Pryor stuffed a duffel bag with surgical instruments and raced to New York City, his brother said.

"He went up to St. Vincent's Hospital and sat around with a bunch of surgeons," Richard Pryor said. "He couldn't stand that, so he hitched a ride with an ambulance and went to work."

Pryor made it to Ground Zero, where he and John Chovanes, another Philly doctor, fought through rubble and debris to save John McLoughlin and Will Jimeno, two Port Authority officers who were trapped in the ruins of the World Trade Center.

Pryor and Chovanes became friends, and Pryor encouraged Chovanes to become a surgeon at HUP. "I'm where I am in life because of John," Chovanes said. "He was a magical and genuine guy. This is such a loss."

Pryor joined the Army Reserve Medical Corps soon after. In 2006, he went to Iraq for the first time, serving with the 344th Combat Support Hospital, in Abu Ghraib.

Many of his colleagues were struck by his decision to go into a war zone voluntarily .

"I asked him why he pushed so hard to go over to Iraq," said Dr. Babak Sarani, a fellow HUP trauma surgeon.

"He said he didn't know how he could sit here, eating a hamburger and drinking a beer, when there were kids over there being shot, and he could help them. He saw it in very black-and-white terms."

Pryor sent constant e-mails detailing the carnage he saw when wounded soldiers and civilians were brought in to be treated.

"Some of those notes broke your heart," Sarani said.

When Pryor returned home, he spoke often - publicly and privately - about the similarities he noticed between violence in Iraq and Philadelphia.

He told some his tales during a storytelling session at the White Dog Cafe, in University City, in October 2006, according to the cafe's Web site.

About a year later, he wrote a lengthy editorial that ran in the Washington Post called "The War in West Philadelphia."

He contended that the violence that was affecting poor inner-city people was largely ignored by the country.

"In Iraq, soldiers die for freedom, for honor, for their country and for their buddies," Pryor wrote. "Here in Philadelphia, they die without honor, without purpose, for no country, for no one."

"Some of us can take blood and gore better, but John took everything personal," Sarani said. "He would lose sleep and sit vigil with his patients. He never stopped caring."

Pryor was also generous with his time. When he wasn't putting in long hours at HUP or trying to squeeze in time with his family, he was tutoring Red Cross volunteers.

Tom Foley, chief executive of the American Red Cross of Southeastern Pennsylvania, said that Pryor had served as a "chief medical adviser" and often had spent hours teaching Red Cross volunteers how to handle traumas.

Pryor's father, also named Richard, had worked for years as a Red Cross volunteer in New York.

"One of the reasons I liked him," Foley said, "was that when you have an extraordinary intellect and frontline experience like he had, it can make you intimidating, but he really related to people."

Pryor also told candid tales of his first tour in Iraq, describing in chilling detail what it was like hiding behind a concrete wall alone for three hours while enemy combatants fired at him.

"I would say he was a courageous guy," Foley said. "He realized that everyone over there was in harm's way."

Pryor spent Thanksgiving with his family in Moorestown. No one imagined it would be the last holiday he would spend with his wife; his daughter, Danielle, 10; and sons Frank, 8, and John, 4.

On Dec. 6, he returned to Iraq for a second tour. He stayed in constant contact with those closest to him.

"He e-mailed me just last week and spoke about all of the wounded Iraqis coming in, and the humanity, or lack thereof," Sarani said. "I told him to take good care of himself."

Now, Pryor's friends and relatives are left to ponder the lessons of his remarkable life.

"Whenever you think there is crime and a lot of bad people in this world, remember guys like John, who are always doing a lot of good," Chovanes said.

"He was compelled to help people," Pryor's brother said, his voice trembling. "I think he did as much as he could." *