Renoir: An Intimate Biography by Barbara Ehrlich White — the standard English-language biography of the painter, with good coverage of the Cagnes years when he continued working despite severe illness. Useful before or after a visit to Les Collettes.
The Autobiography of Alice B. Toklas by Gertrude Stein — the best account of the Riviera and Provence art world in the early twentieth century, written with Stein's characteristic sideways wit. Cocteau, Picasso, Matisse, and the whole scene that produced the Château's portrait collection move through its pages.
Caesar's Vast Ghost by Lawrence Durrell — Durrell's late meditation on Provence: history, landscape, wine, Roman ruins, and the peculiar light that draws artists south. Slower and more ruminative than his earlier work, and better for it.
The French Riviera: A Literary Guide for Travellers by Ted Jones — a useful anthology of writers who spent time on the coast, from Maupassant and Nietzsche to Scott Fitzgerald and Graham Greene. Good for putting Cagnes in its wider cultural context.