WE ALL LIVE WITH HISTORY, and we live in history, and the frontiers between history and imagination are very little more than Chinese screens, removable at will. And a historian is a person who walks his chosen itineraries with his eyes open. It is up to the novelist to pick up the pieces to tie up the loose ends, and to cap the edifice with a conclusion suited to what has gone before."

Richard Cobb is a historian who juggles those screens with genius. His itinerary is late 18th-century France; he knows his way around it in the dark, and arrests us by the evocative poetry of his prose, the pungency of his wit, and the quirky ardor of his personal involvement -- half persuading us that the buried dead he so brilliantly reanimates return his regard. Promenades is not history, though it demonstrates how he goes about nosing his way back into the past in search of revealing detail, showing what clues novels can offer historians, and what a novelist Cobb could be too, if he would.

He first went to France in the 1930s, and has a fixed nostalgia for those pre-war years when Paris was still full of dozing backstreets, nooks that might be country or suburb, before the idiot towers of Montparnasse and the Defense, the scrofulous Beaubourg, and the gaping abyss where the Halles used to stand; before the petites gens, the economically marginal people whose records are the life and blood of his writing, were exiled to desolating highrise housing developments. He has lived a lot in Paris and Brussels; he has been a curious visitor other places -- it's hard to guess where he hasn't been, though he loves Paris best and has a taste for the north with its bleak horizons and gales fraught with "menace, sadness, snow and war."

Childhood, with its acutely concentrated and not-so-innocent perceptions, provides an incomparable frame: Colette's Burgundy, with its bees and figs larger than life, white dresses and coal-dark eyes; Alain-Fournier's mists and damp parks, south of the Lorie, with rusty gates closing off overgrown avenues; Henri Beraud's Lyons, towering like an island in a fantastic Breughel landscape over its two rivers. Other novelists provide clues to the French way of death; to military service, another rite of passage in every Frenchman's life; to the great exodus of 1940, when the French began walking south, like characters in a picaresque novel, lugging suitcases, to escape the Occupation, while a ramshackle government was conducted from hotel bedrooms in a provincial resort, and the streets of Paris lay empty and clean as never before or since. What he likes best in a novelist he finds in Raymond Queneau, a writer of many parts, best known for Zazie dansle Metro. His peculiar attraction for Cobb is the respectable banality of his subject matter, its limited topography (Le Harve), its patterns of habit and speech, offering "the longed-for-guarantee that one day will be much like the last." Cobb rejoices in Queneau's relish for the language of advertisements seen on the sides of truncated houses or in the Metro, extolling detective agencies, cures for frigidity or headaches.

Leaving aside novels, while setting up the framework for a dense and quirkish novel of his own, he writes about Ixelles, a part of Brussels where he lived after the war, with its perfume of tobacco, french fries, and chocolate, its whitened front steps, with multiple bells and visiting cards at each door, caged birds in the window, cats on the sill, and "dogs that, on Saturdays, get drunk with their masters."

Marseilles sends his mind flooding in all directions, a place of arrivals and departures, perched in its broken amphitheater above the sea, where until the age of tankers and international flights, crowds of Arabs and colonial officials, accompanied by tin trunks marked with exotic destinations, jostled one another. He notes the trolleycars of Marseilles, with their poet-sounding destinations that "to the traveller out, to the soldier or the sailor on his way back to discomfort, boredom and loneliness, must yet offer a poignant and tantalizing mirage of domestic peace, daily routine, and the assurance that tomorrow will be like today." He thinks of the prostitutes, of the "luxuriant leafy uglines" of the architecture, the loud clothes, and wonders why the children of Marseilles, surrounded by the sea, harbor life, the luminous heat, the "aromatic desert" beyond, don't pay literary tribute to such beauty and life, but even Marcel Pagnol seems hardly to have been aware that he lived in great port.

There's another unwritten novel in the "iron-voiced" auctioneer, a philistine youth when Cobb first knew him 45 years ago, whose performances at the Hotel Drouot he now watches, entranced. Eloquent, humorous, the auctioneer handles the precious or ludicrous souvenirs of people's lives with an interest and curiosity that make him, like Cobb, "a committed artist, a poet, even a social historian of a kind, endlessly fascinated by breaking into privacy and tottling up the balance sheet of lonely, hidden and unambitions lives."

Cobb is like a loaded sponge, so soaked in his subject that the least touch releases a flow. He can scarely mention a fact without being reminded of something else. Occupied Paris makes him think how the French lack a visual sense -- scenery for them is mere backdrop for intrigue; Queneau reminds him that the biting humor of the French is enjoyed at someone's expense; Marseilles of how people who live by the sea are not the ones who read sea romances; of marriages arranged through petites announces in provincial papers -- "brief exercises in ideal double biographies, a strange dialogue, paid for at so much the line," or of the young men who began military service in '38 and spent the war years sequestered in Africa, missing a whole chunk of their lives so that they don't really speak the same language as those who lived through the Occupation: nuances escaped them. Not Cobb; they are his quarry.

These idiosyncratic wanderings in and out of books and cities and decades were first broadcast on the BBC and keep all the messy "and so forth are so ons" of spontaneous talk, which is what they are: spontaneous, poetic, illuminating, exhilarating.