The door to the nanoworld is ajar. Everyone is trying to get a glimpse. Why such enthusiasm? From nanomaterials to nanomachines, nanotechnologies give promise of a new universe. Welcome to a world of un-stainable surfaces, of communicating dust pulverized into the air or integrated to materials, and of machine-molecules capable of assembling tomorrow’s products. Surfacing, reinforcing, creating new materials, stocking energy: nanotechnologies’ stakes are scientific but also economic. Competition is already raging in Europe, Japan and the United States. Within a decade goods and services related to nanotechnologies should generate a market of billons of dollars!