The Fifth International Conference on Ion Implantation took place in Boulder, Colorado between the 9th and 13th of August 1976. Papers were delivered by scientists and engineers from 15 countries, and the attendees represented 19 countries. As has become the custom at these conferences, the sessions were intense with the coffee breaks and evenings given to informal meetings among the participants. It was a time to renew old friendships, begin new ones, exchange ideas, personally question authors of papers that appeared in the literature since the last conference and find out what was generally happening in Ion Implantation. In recent years it has beome more difficult to get funding to travel to such meetings. To assist the participating authors financial aid was solicited from industry and the Office of Naval Research. We are most grateful for their positive response to our requests. The success of the conference was in part due to their generous contributions. The Program Committee had the unhappy task of the reviewing of more than 170 abstracts. The result of their labors was well worth their effort. Much thanks goes to them for molding the conference into an accurate representation of activities in the field. Behind the scenes in Boulder, local arrangements were handled ably by Graeme Eldridge. The difficulty of this task cannot be overemphasized. Our thanks to him for a job well done.