Jacob van Ruisdael , c.1628-1682, Dutch painter and etcher, the most celebrated of the Dutch landscape painters. He studied with his father Isack and perhaps with his uncle Salomon van Ruysdael, a well-known Haarlem landscapist. He first worked in Haarlem, moving to Amsterdam in 1656. Late in life, he obtained a medical degree and practiced as a physician. Ruisdael's characteristic work shows northern nature in a somber mood. His dramatic skies are usually overcast, throwing a restless flux of light over the countryside. Gnarled, knotted oak and beech trees are rendered with extraordinary accuracy. Ruisdael's later works show great breadth of stroke, dramatizing humanity's insignificance amid the splendor of nature.