TREASON BY THE BOOK: Traitors, Conspirators and Guardians of an Emperor, by Jonathan Spence. London: Penguin Books, 2002, 302 pp. 7.99 UK pounds (paper)

In his short story "The Great Wall of China," Franz Kafka wonderfully evokes the enormity and complexity of imperial China by describing the travails of a messenger struggling to make his way out of the vast palace complex in Beijing to deliver a missive from the emperor. Though he sets out at once, "how vainly does he wear out his strength" as he pushes his way through the palace throng; "still he is only making his way through the chambers of the innermost palace"; still he is fighting his way down the stairways, and crossing the crowded courts; "and so on for thousands of years."

Indeed, as Jonathan Spence says in this remarkable new book, the emperor's court was so remote that for most Chinese it was "like the moon." This posed a problem since the emperor was supposed to rule, and ruling required communication and surveillance. A sophisticated reporting system was therefore utilized to keep him informed of events throughout the realm.

Such a system was particularly necessary because sedition was said to be rife in the land. The ruling Manchus had overthrown the Ming Dynasty some 80 years before, but even now dissidents were still being detected. One came to the attention of authorities in 1728, when an anonymous letter libeling Emperor Yongzheng was delivered to a government official in a remote province.

At once the mighty machinery of the bureaucracy began to grind, issuing reports, counter-reports, accountings and recountings in an attempt to locate the author of the letter. Spence, dean of Chinese scholars, has followed this paper trail, tracing it painstakingly from archive to archive to re-create the convoluted politics of the period.

So detailed is the trail that the author is rarely forced to use conjecture. Instead, every event, even the most unlikely, is recorded. In what other country could officials control the machinery necessary to trace a rumor to a group of chain-gang prisoners seen on a certain path at a certain time years earlier, and then check their files to place and interrogate each suspect?

Each move in the elaborate chesslike operation brings consequences both welcome and unwelcome, and throughout it all the emperor must balance what is good for his constituency with how he is perceived by his subjects.

Contrasted with this painstaking investigation and the assumption of logic and fairness are the atrocious punishments utilized by the state. Various kinds of presses were used to torment the extremities, and for treason itself slicing to death was the recommended punishment -- or, if the culprit were already dead, exhumation and immodest display of the remains of the long-dead delinquent.

Bribery was used to lessen the horror of these punishments. Families of the condemned could, for example, pay the executioner directly and he would give back the head of their loved one for proper burial with the body. The innocent offspring of those adjudged guilty were also often killed, incarcerated or sold into slavery, but those sentenced to death by strangulation could at least pay for the first twist of the rope to be the last.

As for slicing, one executioner is quoted: "If you satisfy me, I will stab you to the heart. Otherwise, even after your four limbs have been sliced away, your heart will still be beating."

It is the combination of literary elegance and barbaric cruelty that lends an irony to all of these machinations and gives the reader a kind of murder-mystery to unravel as spy turns against spy, sedition grows, and power pretends benevolence.

Spence chose to write the book entirely in the present tense, which gives it the kind of realism not often encountered in histories and also an instantaneous believability that is at the same time provisional -- just like life. The author of such extraordinary histories as "The Death of Woman Wang" and "Thek Cham's Great Continent," Spence has here given us one of his most persuasive works.