time Richardson developed an interest in Picasso's portraits and contemplated creating a publication; more than 20 years later, these plans expanded into Richardson's four-part Picasso biography A Life of Picasso. In 1960, Richardson left Cooper and moved to New York City. Author Cooper published frequently in The Burlington Magazine and wrote numerous monographs and catalogues about artists of the 19th century, including Degas, van Gogh and Renoir, but also about the Cubists he collected. He was among the first art critics to write about modern art with the same erudition common for artists of the past; in the years before the Second World War, he was a pioneer in this respect. When his catalogue of the exhibition The Courtauld Collection appeared in 1954, The Times wrote about it: His most important achievement is probably the catalogue raisonné of Juan Gris, which he completed in 1978, six years before his death, and 40 years after beginning it. He was Slade Professor of Fine Art at Oxford from 1957 to 1958 and guest professor at Bryn Mawr and the Courtauld Institute in 1961. Appreciation Cooper is an important figure among art experts of the 20th century, however he was controversial because of his contentiousness and his strong need to be the centre of public attention. He was accused not only of plagiarism and inaccuracies in his works, but also of "flexible ethics" and "cultivating quarrels as much as friends". Cooper not only contributed to The Burlington Magazine as an author, but also served on its board of directors and held shares; he nevertheless tried to force the editor, Benedict Nicolson, to resign, unsuccessfully. In the 1950s, he attacked the Tate Gallery director John Rothenstein, mostly for not supporting Modern Art, trying to get him dismissed. He even managed to anger Picasso so much that he excluded him from his circle and surroundings after he pressed Picasso around 1970 to legalise his children. Misfortunes In 1961, Cooper was found on a road outside Nîmes, heavily injured by stab wounds in the stomach; on his way to the post office in Nîmes to send an article about Picasso's birthday to a London newspaper, he had stopped at a notorious quarter and picked up a young Algerian Fellagha (resistance fighter against the French occupation forces) who had been interned in an open camp nearby. They drove to a lonely area, where the boy drew a