The book (from 1962) also contains an early suggestion of molecular nanotechnology, from Marvin Minsky, called “Where is our microtechnology?”
Clearly it is possible to have complex machines the size of a flea; probably one can have them the size of bacterial cells. Consider the amount of effort that has been spent on miniaturisation of electronic components and circuits; the expenses must total thousands of millions. But all of this has been spent on special jobs. None of the immense effort has gone into developing general-purpose small fabrication equipment...
Imagine small machines fabricating small elements at kilocycle rates. (The speed of small mechanical devices is extremely high.) Again, one can hope to make thousands of elements per second. But the generality of the mechanical approach is much greater since there are many structures that do not lend themselves easily to laminar mask construction.
The book (from 1962) also contains an early suggestion of molecular nanotechnology, from Marvin Minsky, called “Where is our microtechnology?”