We are pleased to present the Proceedings of the NATO Advanced Research Workshop "Syntheses, Properties and Applications of Ultrananocrystalline Diamond" which was held June 7-10, 2004 in St. Petersburg, Russia. The main goal of the Workshop was to provide a forum for the intensive exchange of opinions between scientists from Russia and NATO countries in order to give additional impetus to the development of the science and applications of a new carbon nanostructure, called ultrananocrystalline diamond (UNCD) composed of 2-5 nm crystallites. There are two forms of UNCD, dispersed particles and films. The two communities of researchers working on these two forms of UNCD have hitherto lacked a common forum in which to explore areas of scientific and technological overlap. As a consequence, the two fields have up to now developed independently of each other. The time had clearly come to remedy this situation in order to be able to take full advantage of the enormous potential for societal benefits to be derived from exploiting the synergistic relationships between UNCD dispersed particulates and UNCD films. The NATO sponsored ARW therefore occurred in a very timely manner and was successful in beginning the desired dialogue, a precondition for making progress toward the above stated goal. The discovery of UNCD completes a triadof nanostructured carbonswhich includes fullerenes and nanotubes.

Ultrananocrystalline diamond (UNCD) is one of the important triad of nanostructured carbons which includes fullerenes and nanotubes. This new kind of diamond composed of 3a "5 nm crystallites is an exemplar par excellence of the profound changes in properties that can accompany the reduction in size of a material to low single digit nanometer dimensions. UNCD occurs in two forms: as a dispersed powder made by detonation techniques and as a chemical vapor deposited film. Two communities of scientists, each focused on one of these fields, had up to now, been working independently of each other largely unaware of the vast synergistic relationships existing between them. The NATO Advanced Research Workshop (ARW), the basis for the Proceedings, was held June 7a "10 in St. Petersburg, Russia to bring the two communities closer together. Fostering collaborations between them, to hasten the exploitation of the scientific and technological treasure trove awaiting imaginative explorers to reveal the still largely untapped potential hidden in these materials.

This Proceedings volume will be of interest to a wide audience of scientists and engineers - indeed all those who wish to become familiar with the unique properties of UNCD particles and films that make them potentially very useful for a wide variety of applications. It is particularly noteworthy that much of the Russian work on disperse UNCD is available here in English for the first time. The outstanding experts in the two fields are represented in this volume discussing the basic theoretical concepts underlying the synthesis and characterization of these nanomaterials on the one hand and describing progress that has been made inseveral areas of applications. For UNCD particles, applications include their use in nanocomposites, selective adsorbents, colloidal suspensions, microabrasives, lubricants, quantum dots, cold-cathodes and many others. For UNCD films, their smooth, highly dense, pin-hole free characteristics lead to conformal coatings of very high aspect ratio structures and applications in MEMS, biosensors, as well as electrochemical, and nerve prostheses. The films can be made both n- and p-type conducting thus enabling many potential electronic applications such as high temperature, highly rectifying diodes, FETa (TM)s, thermoelectrics, etc.

The Proceedings will be very useful as an introduction to an important and rapidly evolving field of nanoscience and nanomaterials; as a text for a special topics graduate course; or as a starting point for those interested in the development of new approaches to problems that have hitherto defied solution for lack of suitable materials. It is to be hoped that the wider scientific community will be as intrigued and challenged by these presentations as were the participants of the NATO ARW.