She also pointed out that it had long been known that the work existed, and that the manuscript was written on "original paper and in Verne's ink." Further, Piero Gondolo della Riva, a Verne expert, had Hetzel's rejection letter to Verne in his private collection. "The arguments Hetzel uses in his letter are the same as are annotated on the manuscript," she said.

Inevitably, the appearance of the book has caused a stir, principally among the legion of Verne students, for whom a mystery has at last been solved, but also in the French press, which is once again celebrating the astonishing ability of France's most widely translated author to predict the shape of things to come.

In a preface to "Paris in the 20th Century," Mr. Gondolo della Riva said he was most struck by its dark mood. Until now, he said, critics attributed the pessimism of Verne's later works to personal problems and the deaths of his mistress and Hetzel. "But the pessimism is present at the start of his career," Mr. Gondolo della Riva noted.

In the book, Verne records the travails of a young poet, Michel Dufrenoy, who becomes homeless in a hostile and overcrowded society that is driven by finance and technology and is totally indifferent to culture. It is also, to all intents and purposes, a police state run by all-powerful bureaucrats.

But the book also displays Verne's fascination with technology. Although the first car using the combustion engine wasn't built until 1889, he describes a Paris crowded with cars. "An invisible force with a gas-powered motor made them move," he writes. "It was clear and simple to handle: the mechanic, sitting in his seat, turned a steering wheel; a pedal at his foot allowed him to change the speed of the vehicle instantly."

He describes an instrument "resembling a piano" that serves as a sophisticated calculator in a brokerage house. Stock exchanges across Europe are linked by telegraph. "Further, the photographic telegraph permitted the dispatch over long distances of the facsimile of any writing, signature or design and permitted contracts to be signed at a distance of 5,000 leagues," he writes.

He also imagined a city dominated by electricity, even to the point of describing street advertisements in lights. And he came up with his version of a synthesizer: an "electric concert," in which 200 pianos were linked by electric current to a single piano being played by a musician.