The Thirteenth International Congress of Theoretical and Applied Mechanics was held in Moscow from Monday, 21 August, to Saturday, 26 August 1972. About 2500 participants from 37 countries all over the world attended the congress that was convened by the Congress Committee of the International Union of Theoretical and Applied Mechanics. The local or ganization lay in the hands of the Organizing Committee, established by the USSR National Committee on Theoretical and Applied Mechanics. The USSR Academy of Sciences rendered partial financial help to the organization of th8 congress. The Organizing Committee was assisted by the Institute of Problems of Mechanics of the USSR Academy of Sciences, by the Research Institute for Mechanics of Moscow University, and by the Computing Center and the Institute of Applied Mathematics of the USSR Academy of Sciences. The Bureau of IUTAM had allocated a considerable sum for partial financial support of young scientists attending the congress. The Thirteenth Congress was officially opened on Monday morning at the Kremlin Palace of Congresses by Academician N. 1. Muskhelishvili, President of the Congress, and Professor W. T. Koiter, President of IUTAM. Greeting addresses were offered by: Mr. K. N. Rudnev, Minister, member of the Council of Ministers of the USSR, Academician M. V. Keldysh, President of the USSR Academy of Sciences, Mr. L. N."

We speak of the age of Euler. A justification of this term is provided by a list of scientific terms connected with Euler's name and his many contributions to pure mathematics, well-known in the mathematical community and, in part, covered in this volume. What makes this collection remarkable, though, is the extensive treatment of Euler's contributions outside pure mathematics - astronomy, celestial mechanics, ballistics, music and many other areas. In addition to this survey of his contributions to science, we find also rare, detailed accounts of Euler's family life and the careers pursued by his children and grandchildren. Readers otherwise well-informed about Euler and his work will find here much to enhance their appreciation of this extraordinary scientist and human being.