Book excerpt: Attributing old master paintings is one of the most demanding tasks of the art historian. The stakes can be high, especially when the work in question might indeed be the hand of a great master. The difference in price between an authentic work and one 'in the manner of' a well-known artist can add up to several million dollars. In addition to the fi nancial consequences, a revised attribution can also have dramatic consequences for our understanding of art history. In her fascinating account of connoisseurship in action, Tummers highlights issues regarding the attribution of seventheenth-century Dutch and Flemish art.