Abstract
If we could see molecules in the same way we see the gears of a watch, and if we could manipúlate them, we should be able to fit the bits and pieces of a molecular device much in the same way a watchmaker assembles a clockwork. We human beings have seen molecules from a variety of perspectives, including those of the artists, the quantum chemists or the clairvoyants. However, for most of the XXth century our best photographs have been obtained by means of X ray diffraction. In recent years a series of microscopie and spectroscopic techniques have been developed that take us closer and closer to the dream of the molecular watchmaker.