This book demonstrates the swift progress achieved in the field of diamond for electronic and bioelectronic applications. Predicted to become the 'ultimate semiconductor' in the early 1990s, diamond initially failed to match the impressive developments made with other wide-bandgap semiconductors. The situation is changing, with single-crystal electronic-grade diamond becoming a commercially available material. As importantly, the spectacular properties of single-point defects in diamond, as well as its superlative thermal conductivity, radiation 'hardness' and inherent biocompatibility, are being recognized as vital for devices used in biosensing, quantum informatics, and environmentally challenging applications. Not all recent advances relate to single-crystal diamond. Nanocrystalline diamond (NCD), ultra-nanocrystalline diamond (UNCD) and diamond-like carbon (DLC) are very important forms of carbon, as are multiphase carbon nanostructures and graphene. It features results in all areas of high-performance diamond research. Chemical, electrochemical, and biochemical sensing, including nanodiamond for sensing in-cellular environment and the integration of diamond within biological systems are highlighted.