When nearly 70 in 1897 (he died in 1905), Verne observed, ""I'm working steadily as always, functioning like a machine, and I don't let the furnace cool."" Such deskbound industry doesn't make for animated biography, but Lottman's ""exploratory biography"" of the French novelist is for readers captivated by such works as Twenty Thousand Leagues Under the Sea, Journey to the Center of the Earth and other imaginary voyages. Verne produced so many books that few are up to the prophetic From the Earth to the Moon or to Around the World in Eighty Days, and after the latter, the real Nellie Bly would compete with the creations of the printed page. The novels' sheer quantity requires that Lottman's references to them, and to their origins, occupy much of the book. Still, this first biography of Verne in English in many years has some surprises for his fans. For example, he was primarily a mental traveler. Aside from using his beloved sailboat, he voyaged hardly at all, and traveled aloft only once--years after his Five Weeks in a Balloon. Much of his fiction was not only ill-paying--Lottman (Camus) is informative on Verne's contracts and earnings--but for marketing reasons endured drastic rewriting by his publisher. Yet he refused entreaties to moderate his passionate anti-Semitism, which hardly harmed his sales in a France that was soon to frame Dreyfus. The father of the modern novel of anticipatory science, Verne flagged at times, as he was contractually bound to publish two novels a year, but he gave armchairs wings--and fins. Lottman is PW's European correspondent. Illustrations not seen by PW. (Jan.) FYI: A recently discovered Verne novel, Paris in the Twentieth Century, is published by Random House (Fiction Forecasts, Oct. 14).