This book opens with a helpful note. Harris is offering us a brief lesson in semantics: his quick-thinking, polymath protagonist, the Republican orator Cicero, would have been proud. Lustrum, the illatinate learns, originally meant the den or lair of a wild beast, then an expiatory sacrifice offered by censors every five years and, hence, a five-year period. The arc of Harris’s Lustrum spans five of Rome’s headiest anni — when the megalomania of empire was still a guilty dream yet Roman power-brokers were already growing fat on vast riches from conquered lands: Macedonia, Syria, Gaul. Lustrum is billed a thriller, its author “Britain’s leading thriller-writer”. Harris delights in words and their origins; so it is interesting that “thriller” started life as the Old English thyrlian, to drill down or bore (as in bore a hole), while this book has a more excursive, Greco-Roman dynamic.

Through the story of Cicero’s rise and fall Harris investigates that Classical obsession, power. He considers its value, its origin, its philosophical nature; he chews over power’s praxis and its poison: and he does so via the interplay of rhetoric, drama and realpolitik — all very Ciceronian.

Harris’s own experience of contemporary politics is acute; intelligent parallels are drawn between the political intrigues of the 1st century BC and the 21st century AD. Young aides furiously take notes as dignitaries are driven along in their carriages. Juniors are advised to write everything down, and never to leak their memoranda — “Nothing endures but words”. There’s even a shower-and-foreign-sex-worker scene.

No cheap jibes though; you get the sense that Harris appreciates how hard (some) politicos (in the Greek sense — guardians of the polis) work and how all are eventually trapped in a web of their own, or another’s making. In fact the stories of Rome 63BC are so familiar that one could weary of these chronicles of coded, loaded words, of closed-door dealings and double-crossings. Harris’s narrator sighs: “There are no lasting victories in politics, there is only the remorseless grinding forward of events. If my work has a moral, this is it.”

Lustrum’s cunning, butchering Romans wander around villas admiring the death-masks of their illustrious rivals, they mock Cicero’s lowly origins (cicer = chickpea in Latin) and try to advance his end — he was indeed murdered in 43BC. They oversee bloody sacrifices and turn the known world into their political plaything. Death masks of the period (including possibly that of Julius Caesar) still exist, as do the bones of sacrificed children (Lustrum starts, chillingly, with a child sacrifice).

The characters in Harris’s book once lived and breathed — and his writing is so vivid, so beguiling, one hopes that the long-dead appreciate their immortalisation. But then Lustrum is assiduously researched, and it conjures a trick often missed by historical novels: flavoursome facts give a sense not just of a place and time but of developing lives. Harris remembers that we all exist in our own past and in visions of our future as well as in the present. Lustrum’s characters look forward to a time when bridges to the Tiber’s island will be built, back to a day before the Republic started to rot. It is this concertinaing of history into a series of cogent, life-changing memories, that gives Lustrum its concentrated excellence. Harris also reminds us that his narrator, the real-life slave Tiro, Cicero’s personal secretary, a word-fetishist, developed those shorthand favourites — the NBs, ies, &s and egs that we all still use today. Lustrum reminds us that, however frayed, the thread of human history rarely snaps.

Lustrum by Robert Harris
Hutchinson, £18.99; 464pp Buy the book

Times Recommends

• The 100 Best Books of the Decade
• The Times picks the 50 best paperbacks of 2009
• The conversation: James Ellroy