A quantum dot is a particle of matter so small that the addition or removal of an electron changes its properties in some useful way. All atoms are quantum dots, but multi-molecular combinations can have this characteristic. In biochemistry, quantum dots are called redox groups. In nanotechnology, they are called quantum bits or qubits. Quantum dots typically have dimensions measured in nanometers, where one nanometer is 10-9 meter or a millionth of a millimetre. The fields of biology, chemistry, computer science, and electronics are all of interest to researchers in nanotechnology. Other applications of quantum dots include nanomachines, neural networks, and high-density memory or storage media. Research is being carried out on nano-crystals, self-assembled dots, and gated structures. This book presents leading-edge research from around the world.