This book presents a comprehensive review of research on applications of carbon nanotubes (CNTs) and graphene in electronic devices. As nanocarbons in general, and CNTs and graphene in particular, are becoming increasingly recognized as the most promising materials for future generations of electronic devices, including transistors, sensors, and interconnects, a knowledge gap still exists between the basic science of nanocarbons and their feasibility for cost-effective product manufacturing. The book highlights some of the issues surrounding this missing link by providing a detailed review of the nanostructure, electronic properties, materials preparation, and device fabrication, leading to studies of the structure–property–application relationships. It discusses electronic transport in various nanocarbon interconnects in detail and reviews extensively flexible sensor applications and CNT and graphene transistors. It also presents exploratory research on the usage of carbon nanofibers for energy conversion and storage, and provides a realistic assessment of the challenges faced by nanocarbons in applications to electronics.