A jeweler with an established reputation through the world, Louis Comfort Tiffany was the spearhead of the Art Nouveau movement in the United States. At a time and in a country in perpetual growth, Tiffany succeeded in elevating the decorative to the rank of fine art. Glass was the field of expertise of Tiffany's workshops. There they developed groundbreaking techniques of treatment which produced beautiful effects on glass. Following the examples of Gallé or Daum, Tiffany made the most of this material: playing with colors, opaqueness and transparency... However, his most famous success is his lamps in mosaic of glass, similar to the cathedral's stained glass window. Diving into this prism of colors, the author makes us dream again of the birth of this enduring company.