Pierre-Auguste Renoir (1841-1919) stands out among the great artists for his willingness to paint pictures that are straightforwardly pretty and charming: he chooses familiar and sympathetic human types as his subjects, and depicts them with an appealing immediacy, using an attractively bright and rosy palette. Not all of his four thousand or so paintings are equally good; some fall short on formal grounds, and others, not surprisingly, sink into...