Molecular nanotechnology involves the ability to manufacture objects t
o precise atomic specifications. A central postulate is that any struc
ture that can be specified and that does not violate physical law can
be built. Three pathways to molecular nanotechnology are proximate pro
be technology (the use of improvements of the scanning tunneling micro
scope, STM), biotechnology, and supramolecular chemistry. Combinations
of these technologies appear particularly powerful. The biotechnologi
cal approach should make it possible to use in vitro translation syste
ms to manufacture polymers containing at least 10 times as many differ
ent artificial monomers as there are natural amino acids. These polyme
rs could further adsorb various other molecular devices, and the use o
f STMs should enable the complexes to be arranged into sophisticated m
achines, including molecular computers. The implications include pocke
t superautomated analyzers and the ability to base medical therapy on
the biochemical individuality of specific patients.