Oil sketches by Peter Paul Rubens, created at speed and in the heat of invention with a colourful loaded brush, convey all the spontaneity of the great Flemish painter's creative process. This ravishing book draws from both private and public collections to present in full colour 40 of Rubens's oil sketches. Viewers will find in these informal paintings an enchanting intimacy and gain a new appreciation of Rubens's capacity for invention and improvisation, and of his special genius for dramatic design and colouristic brilliance. The book investigates the role of the oil sketch in Rubens's work; the development of the artist's themes and narratives in his multiple sketches; and the history of the appreciation of his oil sketches. It also explores some of the unique aspects of his techniques and materials. By revealing the oil sketches as the most direct record of Rubens's creative process, the book presents him as the greatest and most fluent practitioner of this vibrant and vital medium. This book is the catalogue of the exhibition that appears at the Bruce Museum, Greenwich, Connecticut; the Berkeley Art Museum; and the Cincinnati Art Museum. The exhibition at the Bruce Museum coincides with the Metropolitan Museum's exhibition of Rubens's Drawings, and a number of joint events have been arranged.