Gustav Klimt's work brilliantly negotiates the borders between the traditional and the modern, the figurative and non-figurative. His subtly erotic portraits, richly patterned landscapes and enigmatic allegorical compositions are at once sensuous and refined, while his extravagant, ornamental style verges on abstraction. Obliged to go his own way when he was denied public commissions, Klimt became the leader of the modernists in Vienna, perhaps the...