Wang Quanyuan was 21 years old, tall, beautiful and full of party spirit when she and 86,000 other troops set out for the hinterlands of China. It was late in 1934, when Mao Zedong and other party leaders decided to retreat from Chiang Kai-shek's forces, who had them nearly surrounded.

Surely that young woman or the 30 others who went with her did not know that they would be marching nearly 4,000 miles over some of the world's harshest terrain, and that a year later they would have completed one of the defining events of the 20th century, now known as the "Long March."

Those women are the focus of Dean King's new book, "Unbound: A True Story of War, Love and Survival" (Little, Brown, 432 pages, $25.99). For several years, King researched the route of the Long March, trekked portions of it, and interviewed some of the remaining survivors. In the book, he unearths the reality of the ordeal, which had become the stuff of legend even before it was finished, with Mao Zedong claiming they'd traveled 7,750 miles. King found it was more like 3,750.

Not to minimize the feat, which is clear as we read about these young women braving gunfire, eating grass, butchering their horses and boiling the lice out of their clothes. King does a marvelous job of re-creating the horror, the battles, the encounters with warlords as well as the political machinations and intrigue, and at times he seems to want to write an authoritative account of the entire Long March. That's an admirable goal, and one in which he has some success, but in reading the book, one can feel the tension between that goal and the desire to tell the stories of the female marchers. Military buffs may appreciate the comprehensiveness, but at times it makes us more general readers feel a little like we're on a Long March of our own.

Still, this is an important book for anyone interested in China today. By the time the Long Marchers arrived in the far north, only 20,000 remained. Wang Quanyuan was not among them. She had been captured by a warlord and kept as a concubine for two years until she escaped, and went on to live a long and difficult life. In 2006, King sat down to interview her about the march, and I couldn't help but wonder about all the change her eyes had seen. In "Unbound," we begin to get a sense for just how long her country's march has been.

Frank Bures is a writer in Minneapolis.