Gerard Dou was one of the most sought-after and best-paid painters of his day. His work was greatly admired for its wealth of detail. A contemporary of his revealed that Dou would spend more than three days painting a single fingernail. Another visitor to his studio claims to have seen him at work with three pairs of spectacles balanced on the bridge of his nose. Dou specialized in small paintings with no more than a few figures. The Quack, however, is an exception. It is Dou’s largest painting by far, with fifteen figures in all. Among them, we see a peasant pushing a barrow containing vegetables, a pancake maker wiping her child’s bottom, and a fish merchant, blithely unaware that she is being robbed of her purse. The scene is set just outside the walls of the painter’s hometown, Leiden. Dou portrayed himself as well, leaning out of a window with a palette in his hand. He would surely have had a reason for placing himself beside the quack. Perhaps his idea was that both are masters of illusion: the bogus doctor deceives by selling useless remedies, the artist by suggesting a reality which is merely paint on a panel.