THE mark of a superior historical novel is not always an erudite rendering of the recorded past but what the author imagines could have happened within the framework of the known.
Put in other words, it is the "what if" factor that often makes for a compelling story, a skill that has been mastered by British novelist Robert Harris, a onetime correspondent for the BBC and a former political columnist for the London Sunday Times and Daily Telegraph.
The most tantalizing premise the 49-year-old author puts forth in "Imperium," his fifth novel, springs from an alluring detail that has survived the centuries as a delectable footnote to the historical record. It is the knowledge that Marcus Tullius Cicero (circa 106-43 BC) -- the superstar orator, lawyer, politician and philosopher of the late Roman republic -- owned a brilliant slave by the name of Marcus Tullius Tiro, who was present at every eventful twist and turn.
Tiro was a formidable intellect who was celebrated for having developed a system of note-taking known as Tironian shorthand, a form of stenography he used to make verbatim transcriptions of his master's speeches and dictation, and anything of importance anyone else said, for that matter, in public or in private. In a culture that prided itself on verbal gymnastics and legal precedent, this was a skill of no small consequence.
That Tiro's countless contributions to his master's welfare went well beyond domestic drudgery was affirmed by Cicero himself, most persuasively in a letter preserved along with 900 or so others, again, thanks to his amanuensis: "Your services to me are beyond count -- in my home and out of it, in Rome and abroad, in private affairs and public, in my studies and literary work." On Cicero's death, Tiro was freed, whereupon he became his mentor's literary executor and an author in his own right.
Among Tiro's writings was a four-volume biography of Cicero that was lost in the Middle Ages after the collapse of the Roman Empire but whose existence was known to the biographer Plutarch and the historian Asconius. It is an imagined reconstruction -- an up-close-and-personal recollection written in the first person toward the end of a life that spanned 100 years (circa 104-4 BC) -- that Harris uses to splendid effect in "Imperium," Latin for the supreme political power that each of the principals seeks and schemes to secure.
It gives nothing away to disclose that Cicero achieved the highest position attainable in the Roman republic -- the consulship -- at the age of 42 and that he did so against all conceivable odds. That is where Harris concludes this first in what is projected to be a three-volume work on Cicero's life and times.
Unlike his chief rival in the Senate forum, the aristocratic lawyer Hortensius, Cicero did not have the advantage of influential family connections, and unlike two other figures in the drama, triumphant generals Pompey and Caesar, he had no army to support his driving ambition. Though Cicero married well, his finances paled in comparison with the legendary wealth of Crassus, who opposed him fiercely. "All he had was his voice," Tiro writes, "and by sheer effort of will he turned it into the most famous voice in the world."
It's a testament to Harris' narrative skill that Tiro speaks with such assurance, but it is the novelist's seamless use of Cicero's own words that is most impressive. In an author's note, Harris acknowledges his debt to the 29 volumes of Cicero's speeches, writings and letters issued by Harvard University Press in its Loeb Classical Library series of works from antiquity; a trove of documentation, it provides incisive commentary on a multitude of subjects, not least of them this observation by Cicero on his favorite subject: "Politics? Boring? Politics is history on the wing! You might as well say that life itself is boring!"
In "Fatherland" (1992), "Enigma" (1995) and "Archangel" (1998), Harris offered provocative 20th century speculations. Accounts of the eruption of Mt. Vesuvius inspired him to craft "Pompeii" (2003), a 1st century thriller that served as a warmup for "Imperium," which is quite possibly his most accomplished work to date. And as Tiro the raconteur continues to spin his timeless tale of human nature, we can cross our fingers that the best is yet to come.
Nicholas A. Basbanes is the author of, most recently, "Every Book Its Reader: The Power of the Printed Word to Stir the World."