The introduction of the scanning tunneling microscope (STM) for electrically
conducting surfaces by Binnig and Rohrer in 1981 was followed by the
invention of atomic force microscopy in 1986 by Binnig, Quate, and Gerber
also for nonconductive samples. The initial interest was in atomic and
molecular resolution, and it rightfully continues also with building molecular
machines by atomic-scale manipulation and industrial applications in the
field of high-density data storage on ultraflat surfaces. The latter topic also
uses the various techniques of scanning near-field optical microscopy (SNOM)
for surfaces without roughness. It was not until 1990 that the capabilities
of AFM for the third dimension started to become recognized, even though
commercial instruments were available since 1989, but funding of projects
aiming for submicroscopic characterization of topology was still not achievable
then and early publications were impeded by referees and editors. Many
authors in the first half of the 1990s did not even give a z-scale to their plots
but stressed only on the lateral resolution on top of 3D objects. It was not
appreciated then that most industrial and biological applications would be
on real-world samples at ambient conditions rather than with artificial test
samples under high vacuum, or with other artificial treatment. Similar experiences
were encountered with SNOM when a new instrument became available
in 1995 with the capability of reliable scanning on rough real-world surfaces
with height differences of more than a micrometer, and again similarly in 1999
when two-dimensional transducers were added to nanoindentation equipment
enabling nanoscratching for novel nanomechanical testing.