Diamond films grown by activated chemical vapor deposition have superlative thermal, mechanical, optical, and electronic properties combined with a very high degree of chemical inertness to most environments. These properties, together with the ability to fabricate films and shapes of considerable size, promise an exciting new material with many applications. Some applications are on the verge of commercialization but many await a few more technological developments. Diamond-like films are already employed in both commercial and military applications. The popular press, as well as the scientific and technological and industrial communities, are increasingly interested in the potential for future development of these materials. Although there are many technical papers and review articles published, there is no Single comprehensive introduction to these technologies. The Scientific Affairs Division of NATO recognized the need and the future importance of these technologies and authorized an Advanced Study Institute on diamond and diamond-like films. NATO Advanced Study Institutes are high level teaching activities at which a carefully defined subject is presented in a systematic and coherently structured program. The subject is treated in considerable depth by lecturers eminent in their fields and of international standing. The presentations are made to students who are scientists in the field or who possess an advanced general scientific background.