Silicon is the most widely used material for modern electronics and is the heart of any computer. The size of computers is continuously shrinking and the PCs becoming more powerful. This is due to the continuous downsizing of silicon device components, so that more devices can be packed in a small area of about 1 sq inch in a PC. As the currently used lithographic process is projected to face physical and chemical limitations, efforts are being made to find new ways of developing miniature devices. Another limiting factor on the use of silicon is that it is a poor emitter of light. The discovery of light from porous silicon led to much research on nanoforms of silicon. It has now been understood that nanosilicon in the form of nanoparticles and nanowires can emit bright light. This bringing new opportunities for using silicon in miniature devices. Developments have led to tremendous research on understanding the properties of nanoforms of silicon and have opened up new frontiers in silicon based optoelectronics, chemical and biological sensors with molecular scale detection, device components, memories and for other biological applications. Possibly leading to the realization of silicon laser as well as integration of optics with electronics using silicon. Leading experts provide accounts of the prospects for continuous silicon use in future electronic devices.* Latest developments in nanoparticles, nanowires and nanotubes of silicon * Focus on nanosilicon - a very timely subject attracting large interest * First time chapters on metal encapsulated silicon clusters and nanotubes