Darrell Griffin Sr. has gotten down to work on his final collaboration with his son and namesake.

The book taking shape beneath his hands is a compendium. It will blend an account of a father's melancholy journey to Iraq with the dire experiences and searching meditations of a son, the latter written down by Darrell Griffin Jr. before a Sadr City sniper's bullet pierced the back of his head in March.

Darrell Jr. was an Army infantry staff sergeant, 6 feet 2 inches of muscled warrior. Married, with no children, he'd been an emergency medical technician in Compton, Calif., before finding his life's work as a soldier.

Although he had eschewed college, he was an avid reader.

Darrell Jr.'s death at 36 left his father grieving and feeling helpless. It was Darrell Sr., a small-business consultant in Los Angeles, who had suggested that his son keep a journal, and who had promised to help him put it in book form when he returned from his second combat tour.

"I thought it would be a great thing for a father and son to do, and at the same time it might help him keep his sanity while he was going through all that over there," Griffin said.

So, hoping to somehow soften his anguish, Griffin resolved to go to Iraq to gain a sense of the final phase of his son's life, to speak with the men he died fighting alongside and "to feel a little of the danger."

He reasoned that it would help him write the book, which would be the fulfillment of a promise, a kind of gift to his son.

Because of his writerly intentions, Griffin obtained permission from the military to travel to the war zone as an embedded journalist. His cause was helped by the fact that three weeks after his son's death, Darrell Jr. had been the subject of a long cover story in U.S. News and World Report. His name was familiar to senior officers, including Gen. David Petraeus, the senior U.S. commander in Iraq.

After Griffin arrived in Baghdad, he tasted the Army life his son relished. He ate in the mess hall where his son had. He shopped at the PX.

He also interviewed the men in Darrell Jr.'s company, with a particular interest in the details of his son's last day.

Since Griffin returned home, life has been knitting its way around the loss of his son.

Film rights to his son's story have been sold. A documentary, including the videotaped interviews Griffin conducted in Iraq, also is in the works.