MARBLEHEAD — Just prior to Memorial Day, a total stranger alerted Harry Christensen to the fact that one of the defining moments of his life was part of a new book.

It was all the more perplexing because Christensen, a Marblehead selectman, hadn't given his permission and had never spoken to, never met, never heard of the author.

The book is titled "Marine Corps Tank Battles in Vietnam," by Oscar E. Gilbert. One brief section includes an account of the day, Jan. 24, 1968, when Marine Cpl. and tank commander Christensen and his comrades ran into advance units of the North Vietnamese Army pouring across the so-called demilitarized zone to join in the pivotal Tet Offensive.

Christensen's actions during the horrific fight that followed won him the Silver Star.

On a visit this month to the Marine barracks in Washington, D.C., part of a group of retired "tankers," Christensen had been approached by a brigadier general who asked, "Are you the Christensen in Gilbert's book?"

A puzzled Christensen quickly found a copy. His first read made him uneasy. It was all accurate, but the passage concerning his service brought a flood of conflicting emotions.

"My heart started to beat. I began to perspire. It was like being back there 40 years ago," he said. Though he believes it is important to talk about his wartime experiences, Christensen worried that this moment, when he had no choice but to kill for his country, had passed into the public domain.

On that January day, the Marines believed at first that they'd happened on a small ambush, a common encounter. But they were soon re-educated by a storm of small arms fire and rocket-propelled grenades.

"The relief column halted about 100 yards from the ongoing fight," writes Gilbert. "Christensen took a ricochet from the tank's armor above his right eye. Temporarily blinded by blood, he was trying to tie a rag over the wound."

As Christensen's tank blazed away at enemy soldiers, he remained exposed above the waist, standing in the open hatch forward of the turret — the only way to get a clear view in the jungle. Enemy soldiers "popped up" with rocket launchers.

"I was killing them as fast as I could," he says. Meanwhile, Capt. Daniel Kent, firing a .45-caliber pistol, stood alongside the tank, helping to direct fire.

"Two rounds entered Kent's back and exited through his chest," writes Gilbert, "splashing Christensen's face with blood." The 21-year-old Marbleheader then attempted to pull his captain into the tank.

"Harry cradled Kent's head, tried to reassure him," writes Gilbert.

Eventually, grenades would blow both men off the tank and destroy it. Christensen went into a ditch.

"From there," writes Gilbert, "he could see Kent's body smoldering in the road."

Gilbert's account ends there.

Christensen, who estimates he'd been wounded up to 11 times, remembers five hours waiting for rescue, thinking the day would never end.

"(U.S. troops) dropped napalm so close I could smell the gasoline," he recalls.

Subsequently hospitalized with permanent injuries, it was the end of Christensen's war.

Reliving that day

He never knew Kent well. A youthful by-the-book Marine officer from Auburndale, with blond hair and blue eyes, Kent kept a professional distance from his men. Twice in the previous month, he'd had Christensen up on charges.

The Marbleheader, now a successful lawyer, beat them both times.

"He was all Marine," Christensen says. "For him to be out there with his pistol took a lot of courage."

Kent earned a posthumous Purple Heart. But there is a movement now to do better by him.

"I wrote a letter to the Marine Corps about a year ago explaining the action and what his role was and how he should have been recognized," Christensen says. "We're waiting."

He apologizes for not writing sooner — it's all been difficult to deal with.

Likewise, Christensen's lieutenant — now a high-ranking officer — has made a careful study of after-action reports and seeks to elevate the Marblehead corporal's Silver Star to the Navy Cross.

The resistance that day likely forestalled an attack on the unprepared, unsuspecting Camp Carroll, saving hundreds of American lives. After-action reports cite enemy deaths at 300 to 400.

"That kind of makes you feel good in one way," Christensen says. "But it makes you feel bad in another." Pulling a trigger and watching human beings drop, "You remember that. It doesn't ever go away."

Author Gilbert got his information from the after-action reports, Christensen speculates.

"Harry Christensen wrote that on too many nights, like thousands of others with similar memories, he relives the day that Captain Kent died," Gordon writes at the end of the book. "When will the Vietnam War finally end? Not until the night when Christensen's hopes are finally realized and he pulls Captain Daniel W. Kent to safety."

The line angered him, Christensen says.

"How does he know what I think?"

But he seemed to reconsider when he contemplated its meaning — that for some, especially those who fought, the war would never end.

"And I'll never pull him safely into the tank."