The information revolution of the twentieth century was brought about by microelectronics based on a simple and common material, silicon. Although silicon will continue to be of central importance in the next century, carbon, silicon's upstairs neighbor in the periodic table, will also be of great impor- tance in future technology. Carbon has more flexible bonding and hence has various unique physical, chemical and biological properties. It has two types of bonding, sp3 and sp2, in diamond and graphite, respectively. The existence of the latter, "7r-electron bonding," is responsible for...