Discovery of one-dimensional material carbon nanotubes in 1991 by the Japanese physicist Dr. Sumio Iijima has resulted in voluminous research in the field of carbon nanotubes for numerous applications, including possible replacement of silicon used in the fabrication of CMOS chips. One interesting feature of carbon nanotubes is that these can be metallic or semiconducting with a bandgap depending on their diameter. In search of non-classical devices and related technologies, both carbon nanotube-based field-effect transistors and metallic carbon nanotube interconnects are being explored extensively for emerging logic devices and very large-scale integration. Although various models for carbon nanotube-based transistors and interconnects have been proposed in the literature, an integrated approach to make them compatible with the present simulators is yet to be achieved. This book makes an attempt in this direction for the carbon-based electronics through fundamentals of solid-state physics and devices.