The atoms and molecules subject to manipulation though nanotechnology are, simply put, among the smallest units to which substances can be broken down.

However, it is now known that even these atoms and molecules are combinations of even smaller units. There are a number of types of these smaller units, which are referred to collectively as elementary particles.

Certain elementary particles are so tiny that their size is not known exactly, but they are thought to be many orders smaller than a nanometer in scale. They are the tiniest units known to us, based on our current level of scientific understanding.

In the first chapter, we explained how nano-scale materials differ considerably from ordinary materials, not only in the size of their components but also in the properties they display.

The greatest cause of those differences is the way in which the peculiar properties of elementary particles, unthinkable in the normal-sized world, make their presence felt in the nano-sized world. These properties of elementary particles are called quantum properties, and entities displaying these properties are called quanta. In fact, these quantum properties at the nano level are the source of nanotechnology's potential for opening up new roads of innovation.