This volume contains the proceedings of the conference on "Atomic and Nanometer Scale Modification of Materials: Fundamentals and Applications" which was co-sponsored by NATO and the Engineering Foundation, and took place in Ventura, California in August 1992. The goal of the organizers was to bring together and facilitate the exchange of information and ideas between researchers involved in the development of techniques for nanometer-scale modification and manipulation. theorists investigating the fundamental mech anisms of the processes involved in modification, and scientists studying the properties and applications of nanostructures. About seventy scientists from all over the world participated in the conference. It has been more than 30 years since Richard Feynman wrote his prophetic article: ''There is Plenty of Room at the Bottom" (Science and Engineering, 23, 22, 1960). In it he predicted that some day we should be able to store bits of information in structures composed of only 100 atoms or so, and thus be able to write all the information accumulated in all the books in the world in a cube of material one two-hundredths of an inch high. He went on to say, "the prin ciples of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom. " Since that time there has been significant progress towards the realization of Feynman's dreams."