GEORGE PAINTER won instant fame for his biography of Marcel Proust when the first volume came out in 1959 (volume II followed in 1965). The book immediately became the standard biography of the novelist, and was hailed in France as warmly as it was in Britain. From time to time Painter was also in the news defending the authenticity of the Vinland Map, a supposed 15th-century copy, discovered in 1957, of a much earlier Norse or Icelandic map of the North American coast.

George Duncan Painter was born in Birmingham in 1914. He was educated at King Edward’s School, Birmingham, and at Trinity College, Cambridge, where he was a scholar and soon became known as a brilliant classicist, winning various medals and honours. He taught Latin for a short while at Liverpool University in 1937, and in 1938 joined the Department of Printed Books at the British Museum. He was to spend the rest of his career there, becoming assistant keeper in charge of 15th-century printed books in 1954.

At that time, the museum was staffed largely by gentleman scholars, who were left to get on with their lives and their work in their own way, and this suited Painter perfectly. He was a quiet, deeply learned man, who would generally be seen reading a book even as he walked along the street.

He worked at first on the General Catalogue of Printed Books, and eventually became an outstanding expert on incunabula, or books printed before 1500 (in his Who’s Who entry he described himself as an “incunabulist”). The British Museum (now British Library) catalogue of 15th-century books was begun in 1903, and is still not quite finished, but Painter made substantial contributions to it.

From quite early in his life, he also took an interest in French literature, and his first book was a critical biography of André Gide, published in 1951. In the same year, he published a sequence of lyric poems about an unhappy love affair, The Road to Sinodun: Poems, but it was to be his only volume of verse. He was encouraged to pursue his wide range of interests by his friend and colleague at the museum, the novelist Angus Wilson, who firmly believed that museum staff, while performing their duties conscientiously, should also be men of broad intellectual distinction.

Painter translated works by Gide and Proust, and these interests culminated in his great Proust biography. It was very thoroughly researched and beautifully written, and won the Duff Cooper Memorial Prize. With the passage of time, some aspects of it have been challenged: it identifies the characters of Proust’s À la recherche du temps perdu too firmly with real people whom Proust knew, and its analyses of personality have too markedly Freudian a flavour for current taste. But it is still an essential companion to Proust’s writings.

In 1965 he also published (with R. A. Skelton and T. E. Marston) The Vinland Map and the Tartar Relation. This was a study of the long-controversial map, asserting its authenticity. In spite of his retiring manner, Painter could be very spirited in defence of his views, and when Russian scholars suggested the map was a forgery, he was reported as saying: “If Russians had really taken the trouble to read our book — which they may have been unable to do — they would have seen that they were wrong.”

However, in 1974, some American experts in small particle analysis examined the map, and declared that the crystalline structure of the ink made it certain that it was manufactured after 1920. One of the American team remarked that it was no more plausible that such ink was used in 1400 than that Nelson’s flagship was a hovercraft. But Painter stuck to his guns, and indeed some doubt was cast on the earlier experts’ testimony in 1987, when a University of California physicist analysed the ink again and reported that it still remained feasible that the map was genuine.

Painter worked serenely on during the 1960s upheavals in what was now destined to become the British Library, a separate institution from the British Museum that he had joined as a young man. He retired in 1974, in which year he was appointed OBE.

In 1976 he brought out a “quincentenary biography” of William Caxton, and in 1977 the first volume of another venture in French literary biography: Chateaubriand: The Longed-for Tempests. This won the James Tait Black Memorial Prize, but was not quite so well received by the critics as the Proust book had been. In it, Painter carefully compared Chateaubriand’s own account of his life in Mémoires d’Outre-Tombe with the ascertainable facts. However, the work was thought by some to be a rather laborious demonstration of what had long been known: that Chateaubriand’s autobiography was a highly imaginative work. Painter never published the intended second volume of the book.

In retirement in Hove, he brought out Studies in 15thCentury Printing (1984), and worked on a revised and enlarged edition of his Marcel Proust. When this appeared in a one-volume edition in 1989, he gave another demonstration of his spirit. At a party to celebrate publication, given by Chatto & Windus, one of the directors praised Painter for his generosity, saying that when the book first came out, the author had offered to forgo some of his royalties if that would help the publisher. There were disapproving mutterings from a number of other biographers present, and when Painter spoke, he complained sharply at being portrayed as a blackleg at his own party.

He is survived by his wife, Joan, whom he married in 1942, and by two daughters.

George Painter, OBE, author and museum official, was born on June 5, 1914. He died on December 8, 2005, aged 91.