"Claude Monet, the leading figure in the Impressionist movement, was also a great collector. He lavished great attention on his acquisitions, whether selecting works to buy or taking care of the paintings given to him by his artist friends. He was capable of spending very considerable sums to obtain major works by the likes of Renoir or Cézanne. By dint of paintstaking research worthy of a complex police investigation, Marianne Mathieu and Dominique...