The Fifteenth Rare Earth Research Conference was held June 15-18, 1981 on the Rolla campus of th.e University of Missouri. The conference was hosted by the Graduate Center for Materials Research, the College of Arts and Science, and the School of Mines and Metallurgy. It was expected that the conference would provide a forum for critical examination and review of the current and important trends in rare earth science and technology. To this end, over 170 papers were presented in both oral and poster sessions by researchers representing some nineteen countries. The program committee was particularly gratified to see the diversity of effort being devoted to rare earth research by different disciplines allover the world. The collection of refereed papers in this volume attests to the fact that the objectives of the program committee were indeed realized. A high point of the meeting was the presentation of the Frank n. Spedding Award to a most distinguished colleague, Professor Georg Busch, Eidgenossische Technische Hochschule, Zurich. Prof­ essor W. Edward hi"allace, University of Pittsburgh, recipient of the first Frank H. Spedding Award made the presentation to Professor Busch who then gave the Plenary Address.