Harmony in Blue and Gold: The Peacock Room in the Freer Gallery of Art, Washington, DC, is the only surviving interior by James McNeill Whistler. The room has been disassembled and moved four times, with accompanying restoration and conservation treatments. Whistler had a strong interest in surface, diaphanous materials and color patternings. A team of conservators, in coordination with Freer technical and curatorial staff, is investigating Whistler's techniques, materials, subsequent overpaint and obscuring coatings. The information obtained is being used to develop treatments employed in the cleaning of the Peacock Room.