Scanning tunneling microscopy appeared as a new method to deal with atoms,
molecules, and nanometer-scale structures. It was the first of a growing fa
mily of local probes for imaging and measuring, which can serve at the same
time as tools. Local probe methods have changed the way we perceive, think
about, and treat atomic structures, and have brought about a new appreciat
ion of mechanics. They play a central role for science and technology on th
e nanometer scale and sill allow us to build systems of the same complexity
as used by nature, which has built life on nanofunctionality. [S0034-6861(
99) 04402-5].