The Japanese artist Riichiro Kawashima wrote: 'Quite a long time ago [1913], when Picasso was living in a fashionable studio overlooking the Montparnasse cemetery . . . I asked him: 'Do you really like Matisse?' He widened his big, bright eyes and said: 'Well, Matisse paints beautiful and elegant pictures. He is understanding.' . . . When I visited Matisse in Nice four years ago [1929], I asked him: 'What do you think of Picasso?' After a moment of silence, he said: 'He is capricious and unpredictable, but he understands things.' ' It is not just that Yve-Alain Bois' book Matisse And Picasso paints an immensely enjoyable picture of appreciation, symmetry and often intense dialogue between the two giants of modern art, illustrating it with startling juxtapositions, from its cover - Henri Matisse's The Dream (1940), and Pablo Picasso's extraordinarily similar Woman With Yellow Hair (1931) - to Picasso's work when he was mourning Matisse. This is nothing so simplistic as direct comparison. What Bois writes is a story about how two creative geniuses fed off each other, spurred each other on, and dragged each other back to the main game in a way that no one else could have. It would be going too far to say this book postulates that one could not have achieved all he did without the other, but this extraordinary exploration of commonality of themes, beliefs and motifs reveals how much they thought about each other's work despite the fact the two artists could not have been more different. Bois takes up the men's tale where others have left off or only touched upon - the second part of their careers, during the 1930s, 40s and early 50s. When the book starts, Picasso is close to 50 and Matisse is in his 60s. From the beginning, the artists' exchanges - verbal, written and artistic - were often heated, even bitter. But they had a rare understanding of each other's work and borrowed from each other, sometimes shamelessly; they learned from the other's experiments and experiences, and they often paid tribute to each other. Matisse and Picasso danced a complicated tango, writes Bois, who makes further sense of their exchanges by covering them chronologically through 25 years of peak productivity. Their interaction involved caricature, 'completion', where one told the other he had not gone far enough, intense competition, and a territorial tug-of-war. The truth was, as they both partially acknowledged, that they needed each other to invent and reinvent themselves. They also reserved the right to take pictorial blows at each other but deeply resented criticism of the other by a third party. It did not stop sharp tit-for-tat exchanges and long periods when the two ignored each other. Bois' excellently researched and annotated book quotes Matisse writing to his daughter Marguerite in 1926: 'I have not seen Picasso for years . . . I don't care to see him again . . . he is a bandit waiting in ambush.' But when they paid attention to each other, it was with a purpose that makes the final chapter particularly touching in a way no art history treatise could have managed. When Matisse died in 1954, Picasso did not attend the funeral. What at first seemed like indifference was terror in the face of an abysmal void. For half a century, his debate with Matisse had been a structuring force, writes Bois. 'But now, 'who was there to talk to?' ' Six weeks later, Picasso reacted, with the Women Of Algiers, which he had often wanted to tackle, but now did with reference to Matisse. His set of 15 canvasses were completed in just two months, including version H, the most Matissean - all with bright colours, loose texture and large unpainted areas. In October the following year, he painted 11 canvasses on a theme over which he and Matisse had been engaged in pictorial conversation back in 1932. But probably the most Matissean in Picasso's oeuvre appears in the last chapter. Woman In A Rocking Chair (1956) displays the same brushwork, the flat planes of pure colour, the reserved white halos around objects, the blank face, even the palm tree. It is also so Picassoesque, with the dismembering and remembering of the body, a crumpled knot at the centre, a shark-like belly, a phallic right arm and neck. Picasso, Bois writes, had co-fathered a canvas with his competitor. Bois has benefited from some excellent editing: good translation and high-quality plates always close to the text. His book is more than the catalogue to an exhibition - Matisse And Picasso: A Gentle Rivalry, at the Kimbell Art Museum in Fort Worth, Texas. The exhibition offers the chance to see many works exhibited and published for the first time. That is a rare opportunity made much more publicly accessible in this superb book. Matisse and Picasso by Yve-Alain Bois Flammarion $500