Georges Seurat was a great artist at 25, when he launched his arresting studies for his monumental painting A Sunday on the Island of La Grande Jatte. Six years later, in 1891, he died of diphtheria. A deeply private man whose friends were surprised to find, at his death, that he had a mistress and two sons, Seurat relied on others to speak for him. The explosive impact of La Grande Jatte, the signature painting of the Art Institute of Chicago, was recognized at once when it was first exhibited in 1886, thanks largely to the sympathetic eye of a brilliant art critic, anarchist, and bomb-making terrorist named Félix Fénéon. The coincidence of a Museum of Modern Art exhibition of Seurat's drawings—"the most beautiful painter's drawings in existence," his close friend Paul Signac called them—and the publication of Luc Sante's vivid translation of Fénéon's fragmentary Novels in Three Lines invites a fresh look at the painter and his spokesman. Rarely do avant-garde art and radical politics cross-pollinate in quite this way.