Guy Gavriel Kay, the author of such critically acclaimed works as “Ysabel,” “Tigana” and “The Sarantine Mosaic” (a duology), has produced a new masterpiece: “Under Heaven,” a tale of ghosts, feuds, power and love, set against the sweeping backdrop of the Empire of Kitai, an analogue of Tang Dynasty China.

The protagonist, the eminently sympathetic Shen Tai, is the second son of the late Shen Gao, one of the most respected Kitan generals in recent memory. Near the end of his life, Shen Gao told his son of his role in a decades-old battle on the shores of the lake Kuala Nor–a historic victory at the cost of forty thousand men, both Kitan and Taguran–and of his regrets since. Tai, upon his father’s passing, retreats in mourning to Kuala Nor, where for two years, he buries the dead, Kitan and otherwise–they are indistinguishable–by day and is haunted by the wailing of their ghosts at night.

Tai’s isolation comes to an abrupt end when, to honor his lakeside vigil, the princess Cheng-wan, the daughter of one emperor and consort to another, makes him an impossibly lavish gift: two hundred and fifty of the famed Sardian horses, of which any one steed alone is a tremendous reward. In a single stroke, she places him squarely in the center of imperial politics and court intrigue, a world where he finds himself utterly unprepared and in often-mortal peril. Tai learns to navigate these treacherous waters–by necessity, at great speed–even as the reader beside him is plunged headlong into a realm of itinerant poets, politically savvy concubines, ambitious ministers and strategically overlooked princes. With another war threatening the imperial dynasty itself, everybody of any importance takes an interest in his Sardian horses, and therefore in him. So, too, did this reader.

“Under Heaven” is a master-work of epic proportions, which at once captures the essence of an entire people and society, and delves into the lives of the individuals who populate his story, from the crippled beggar on the street to the courtesan-turned-concubine whose servant he once was. Kay’s literary style, too, evokes the cultural legacy of imperial China; his descriptions of politics, his poetry (or rather, translations thereof) and his command of the full spectrum of human emotion echo the Four Great Classics and the preeminent scholars and poets of the Tang dynasty. This reader’s one gripe, admittedly a relatively small one, lies with Kay’s translations; “Under Heaven” includes, for example, an English rendition of Li Bai’s famous poem “Reflections on a Quiet Night,” a translation which does not quite manage to reproduce the cadence or meaning of the Chinese, beyond the bones of the literal verse. Kay fares better with original poetry; at one point, Tai and his estranged older brother find themselves improvising before a very literate audience–a theme common to many of Kay’s works–and their verse is actually quite good.

“Under Heaven” is in many ways a historian’s novel; never does Kay lose sight of the butterfly effect–the actions of the lowliest beggar do, in this case, alter the course of an empire. Throughout the book is a pervasive sense of history, an awareness among the major players that their deeds will be recorded for, and judged by, their heirs in perpetuity. It makes for a potent sense of realism, a deep investment in the lives of the characters and a story of breathtaking grandeur.

“Under Heaven” arrives in stores in the United States on May 3, and the author will be in Menlo Park for a reading on May 9.