Everyone, I suspect, has a favourite photograph by Henri Cartier-Bresson. Mine shows two couples picnicking beside what I have always thought was the Marne River but turns out to be somewhere else altogether. Juvisy (1938), as it is now titled, depicts urban workers relaxing near a man-made pond in the suburbs of Paris. This is indicative of the exhaustive research of Peter Galassi and his colleagues, who have brought to light a huge amount of new information on Cartier-Bresson and his photographs. Their book has been published to accompany a Cartier-Bresson exhibition at the Museum of Modern Art, New York, where Galassi is chief curator of photography.