The WIlton Diptych is one of England's greatest surviving medieval treasures, now in the collection of the National Gallery, London. This beautiful and enigmatic painting depicts King Richard II being presented to the Virgin Mary and Christ by John the Baptist and two English kings, revered as saints. The brilliant colour and lavish use of gold give it the appearance of a luxury object, yet its primary function was religious, as a portable diptych for the king's private devotions. The authors present a fascinating account of the iconography, historical context and style of this unique and precious object, together with a detailed explanation of the materials and techniques used to make it. They also discuss the likely identity of the artist, and the possible evidence that this picture was known to and referenced by William Shakespeare in his play Richard II. New photography, including exquisite details, gives unprecedented access to this remarkable painting, while the latest infrared imaging reveals hidden underdrawings.