A conference was held in Rome at the Hall of Congresses of the National Council of Research between 11 May and 14 May 1970, under the general theme, Trends and development in the Reckoning of Position and Course at Sea, Beneath the Sea, in the Air and in Space. The conference was sponsored jointly by the Italian, British, French and German Institutes of Navigation with the cooperation of the American Institute. A list of papers presented, with a summary of most of them, appears below. A selection of these papers will be published in this and subsequent numbers of the Journal. The papers have been arranged in an order that corresponds loosely with their subject.