An eighteenth-century French lyre guitar (a variant of the familiar European guitar) was examined and treated during 1995-96. Visual and technial analysis revealed that extensive adhesive and material failure had occurred overall, leading to severe deformation of the wooden plates comprising the instrument, and the loss of decorative as well as structural elements. The treatment of the instrument relied on a careful balance of conservation and crafts techniques. The treatment was informed by the multidisciplinary approach inherent in objects conservation, which is ideally suited to the composite (and functional) nature of musical instruments.