Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online.Molecular electronics is an interdisciplinary theme that spans physics, chemistry, and materials science. The unifying feature of this area is the use of molecular building blocks for the fabrication of electronic components, both passive and active. The concept of molecular electronics has aroused much excitement both in science fiction and among scientists due to the prospect of size reduction in electronics offered by molecular-level control of properties. Molecular electronics provides means to extend Moore''s Law beyond the foreseen limits of small-scale conventional silicon integrated circuits.