Earlier efforts in the field of thermal analysis were concerned with the demonstration of the applicability of techniques to a broad spectrum of materials and to establish the relationship of such techniques with other more accepted method. While such efforts will and should continue, the Third International Conference was unique in that the first standards were disclosed for differential thermal analysis. This was the culmination of the international, cooperative effort of the ICTA's Standardization Committee. The standards currently are available from the United State's National Bureau of Standards. Thus, thermal analysis can be considered to have attained its majority. Reali­ zation of full maturity can be expected in the near future. Inclusion of plenary lectures in these volumes represents a significant de­ parture from previous Conferences. This change is the result of the ICTA's recognition of its educational responsibilities. In the Foreword of the Proceedings of the Second Inernational Conference, Professor L. Berg expressed the hope that thermal methods of analysis would find wider application in science and technology. The citation above, together with the papers presented, indicate the fulfillment of this hope. Xerox Corporation C.B. Murphy Rochester, N. Y., U.S.A. President, ICTA, 1968-1971 XIII PREFACE For the past two decades thermo analytical methods have reached a stage of considerable importance, which is particularly due to the developments in the area of instrumentation.