The scope of the present book encompasses the developments and applications of diamond CVD, starting with a brief description of atomic and crystal structures of diamond and a review of the various processing techniques used in diamond CVD. It is followed by an extensive discussion of fundamental phenomena, principles and processes involved in diamond CVD, with emphasis on the nucleation and early growth stages of diamond during CVD. Diamond nucleation mechanisms, epitaxy and oriented growth are discussed on the basis of experimental observations. The nucleation enhancement methods developed to date are summarized. The effects of surface conditions and deposition parameters on surface nucleation are described.