In Lindsey Hilsum’s book “In Extremis: The Life and Death of the War Correspondent Marie Colvin,” there is a passage describing Colvin’s ordeal behind Chechen-rebel lines over Christmas of 1999. After coming under sustained Russian bombardment outside Grozny, the American-born reporter, then aged forty-four, was forced to trek out of the war zone over the snow-covered Caucasus mountain range to reach safety in neighboring Georgia. There were many bad moments, and, at one point, driven to exhaustion, Colvin considered lying down in the snow and sleeping. It was the opposite impulse of the one that drove her forward throughout her life. Colvin survived her Chechen experience and a dozen or more equally dangerous episodes during her twenty-five years as a war reporter, but, a month after her fifty-sixth birthday, in February, 2012, her luck ran out, in Syria. The Assad regime’s forces fired mortars into the house where she was staying, in the rebel-held quarter of Homs, and she was killed.

Colvin’s life has been memorably chronicled by Hilsum, a friend and colleague who lived and worked alongside Colvin in many of the same war zones, and whose home base was also London. (Full disclosure: I knew Colvin and am a friend of Hilsum’s.) At a time when the role of women is being reëxamined and has rightly galvanized public attention, Colvin’s tumultuous life has inspired a number of recent accounts, including the feature film “A Private War,” starring Rosamund Pike as Colvin. But it is Hilsum’s biography, written by a woman who both knew Colvin and had access to her unpublished reporting notes and private diaries—a trove of some three hundred notebooks—that seems to most closely capture her spirit.

As told by Hilsum, Colvin’s life was an unreconciled whirl of firsthand war experiences—many of them extremely dangerous and highly traumatic—London parties, and ultimately unhappy love affairs, laced through with a penchant for vodka martinis and struggles with P.T.S.D. Colvin was a Yank from Oyster Bay, Long Island, and Yale-educated, and she wanted to follow in the footsteps of the trailblazing war correspondent Martha Gellhorn—her Bible was Gellhorn’s “The Face of War”—but she never wrote a book herself, and was little known to her countrymen, making her name, and the bulk of her career, instead, inside the pages of Rupert Murdoch’s Sunday Times, a British broadsheet with a tabloid soul. From 1986 onward, when the Sunday Times hired Colvin, the editors appear to have happily taken advantage of her lifelong hunger for professional affirmation, a chronic willingness to throw herself into danger in order to get scoops, and her considerable personal charm, which, early on, earned her the trust of roguish political players like Yasir Arafat and Muammar Qaddafi.

Indeed, some of the most startlingly humorous episodes in “In Extremis” have to do with Colvin’s interactions with these two leaders. The first time she met Qaddafi, the Libyan dictator, she was ushered into his bunker’s underground bedroom, where he appeared before her wearing a padded flight suit and lizard-skin slippers, and announced, “I am Gaddafi!”

At the end of the interview, during which he had said he was ready to hit US targets anywhere in the world and described the conflict between the US and Libya as being like the Crusades, he put his hand on her thigh and asked if he could see her again, as if this were a date. “Why don’t you call me?” said Marie.

Colvin became so well acquainted with Arafat, the legendary Palestinian leader, that she sometimes travelled with him on his airplane, and soon resolved to write his biography. The fact is, she probably became too close to him. As Arafat’s wife, Suha, told Hilsum, “Arafat trusted Marie like no other journalist. She had his confidence. If he wanted to say something, he would tell her exclusively. We felt she was one of us and not an intruder.” Once, while Colvin was staying at the Hilton in Tunis when Arafat was away, a senior P.L.O. apparatchik drunkenly tried to bash down her door. According to Suha, Colvin told Arafat about the incident upon his return, whereupon Arafat took the man aside and warned him, “ ‘Mary is under my protection—if you dare touch a hair on her head you will be in prison!’ ” In another episode, Colvin joined Arafat on a visit to Libya to see Qaddafi in his fortress lair:

After awhile, Gaddafi walked in, resplendent in robes. He greeted Arafat and then turned.

“Mary,” he said—neither Gaddafi nor Arafat ever learned to pronounce her name—“What are you doing here?”

“She’s with me,” said Arafat. Marie thought it sounded as if he were boasting that she was on his arm at a London premiere.

“What happened to your nose?” asked Gaddafi.

The scars from her encounter with a Palestinian stone-thrower were still evident, but Arafat launched into an entirely fictitious version of the story in which the culprit was not a Palestinian but an Israeli settler. After a few more minutes of surreal chat, the two leaders disappeared for their meeting.

Such stories crop up again and again in Hilsum’s account, and so do they, evidently, in Colvin’s confessional notebooks, in which she chronicled her memories, fears, dreams, and aspirations, as well as her musings about the men in her life. Personal happiness seems to have mostly eluded her. We are also privy to some of Colvin’s love letters and the private e-mails she wrote and received from some of her lovers, friends, and relatives; Hilsum has been a sensitive curator with these, but some extracts still make for uncomfortably intimate reading. We learn, for instance, that Colvin had body-image issues, that she suffered miscarriages, that she had betrayed one husband (she had two marriages, both failed)—and so forth.

Colvin’s womanhood is, of course, a major selling point of her legacy, much as it was for predecessors like Gellhorn and Lee Miller, the idea being that these were women who made a name for themselves in a man’s world—because war, the business of killing and dying, is still mostly a masculine domain. Hilsum, who knows a great deal about these topics, first met Colvin in 1998, in Djibouti, when the two shared a risky flight with a Ukrainian pilot flying a dodgy airplane into war-torn Eritrea; the experience, Hilsum writes, made the two fast friends. Thirteen years later, they had dinner, in Beirut, a few days before Colvin took off on her final, doomed trip into Syria, and, on the night before Colvin was killed, Hilsum had interviewed her over Skype, from London, for Channel 4 News. “I had known her so fleetingly,” Hilsum writes. “A dinner in Tripoli, a bumpy drive through the West Bank, a drink in Jerusalem. And now she was gone. There was so much I didn’t know about Marie, things she had hidden from me, or that I had chosen not to see. What drove her to such extremes in both her professional and personal life? Was it bravery or recklessness? She was the most admired war correspondent of our generation, one whose personal life was scarred by conflict too, and although I counted her as a friend, I understood so little about her. As grief subsided, I thought of her no less often. She was always there, her ghost challenging me to discover all that I had missed when she was alive.”