Containing over 200 papers, this volume contains the proceedings of two symposia in the E-MRS series. Part I presents a state of the art review of the topic - Carbon, Hydrogen, Nitrogen and Oxygen in Silicon and in Other Elemental Semiconductors. There was strong representation from the industrial laboratories, illustrating that the topic is highly relevant for the semiconductor industry.The second part of the volume deals with a topic which is undergoing a process of convergence with two concerns that are more particularly application oriented. Firstly, the advanced instrumentation which, through the use of atomic force and tunnel microscopies, high resolution electron microscopy and other high precision analysis instruments, now allows for direct access to atomic mechanisms. Secondly, the technological development which in all areas of applications, particularly in the field of microelectronics and microsystems, requires as a result of the miniaturisation race, a precise mastery of the microscopic mechanisms.