Book excerpt: The catalogues of the Paris Salons from the turn of the century provide a unique archive of illustrations of the decorative arts at a pivotal time in their development. These volumes contain over 5,500 illustrations of items of jewellery by leading designers such as Boucheron, Chaumet and Lalique. The pictures have been sourced and re-photographed from the original and often rare catalogues. They have been rearranged alphabetically by artist-designer thus providing an indispensable and practical reference for this seminal twenty year period. They are a unique source for identification and authentication and an invaluable key both to design ideas and the jewellery of the period. AUTHOR: Alastair Duncan is a consultant on nineteenth and twentieth century decorative arts to Christie's, New York. He is author of books, catalogues and articles on this and related subjects and one of the world's foremost authorities on the subject of Art Nouveau. 8 colour and 2500 b/w illustrations