Taxi driver Wang Jun navigates the streets of Beijing, a city filled with wrecking balls, bulldozers and rubble as it prepares for the 2008 Olympics. The son of a prominent government official, Wang knows he is a disappointment to his father, who paid for a first-class education to prepare him for a career. Instead, after a nervous breakdown, Wang dropped out of university and ekes out a living for himself, his wife and their daughter. The monotony and anonymity of his job suit him.

One day, though, Wang's life changes dramatically when a disturbing letter falls from his car's visor. "I am your soul mate," the writer says, claiming to have been his companion through six incarnations, claiming to watch his every move, claiming, moreover, that for more than a thousand years, the two have been doomed to a violent end.

"Fate condemns us to bring about the other's downfall," the writer warns, recounting their past encounters in a horrifying series of letters. Barker renders in gory, vivid detail a bloody history of cruelty, exploitation, betrayal and greed.

During the Tang Dynasty in 632 A.D., Wang is a boy called Bitter Root, castrated by his mother, Sorceress Wu, after impregnating his sister. Months later, his embalmed genitals hanging in his leather pouch, Wu sells him as a eunuch, "a gift" to the emperor. His soul mate is his own daughter — debased, brutalized and forced into prostitution.

In 1213, under the Jin Dynasty, they are street urchins, struggling to survive after a Mongol invasion wreaked havoc and famine in the city of Zhongdu.

In 1542, they live in the imperial harem: Wang is Concubine Bamboo, brought to the Forbidden City when barely 15 years old, carried on a palanquin through a landscape strewn with corpses. Once again China is ravaged by famine.

Susan Barker

In 1836, he is British, investigating the customs of the Tanka people, befriending and eventually murdering his soul mate, an impoverished Tanka boy.

In 1966, they are Yi Moon and Zhang Liya, students at the Anti-Capitalist School for Revolutionary Girls, where those who lack appropriate fervor are punished brutally. Moon is bullied ruthlessly, called "a capitalist parasite"; Zhang, the daughter of a high-ranking party official, tries to protect her, but their friendship ends tragically. Who is sending these unsettling letters?

That's the mystery that propels Barker's ambitious, enthralling tale, a deft melding of past and present, myth and reality, longing and torment.

Linda Simon's latest book is "The Greatest Shows on Earth: A History of the Circus."