Mechanics of the 21st Century Proceedings of the 21st International Congress of Theoretical and Applied Mechanics, Warsaw, Poland, 15-21 August 2004

st The21 InternationalCongressofTheoreticalandAppliedMechanics (ICTAM04) took place August 15 - 21, 2004, in Warsaw, Poland. It was organized by Polish National Committee of IUTAM, Institute of Fundamental Technological Research of the Polish Academy of Sciences (IPPTPAN)andWarsawUniversityofTechnology. TheCongressvenue was the main building of Warsaw University of Technology. The idea of congresses devoted to mechanics, can be traced back to a conference on problems of?uid mechanics in Innsbruck, 1922. It was organized by four individuals, whose names, are and will, remain very wellknowntonextgenerationsofscientists, C.W.Oseen, T.Levi-Civite, T.vonKarm ́ ́ ́ an, andL.Prandtl. Thisconferencewassofruitful, thatthe organizers decided to arrange similar meetings in the future, every four years, and to extend the scope of the future meetings to include solid mechanics. Hence a series of meetings started eighty years agowiththe st 1 ICTAM held in Delft, Netherlands. From the meetingsoftheCongress Committee sprang the idea of a more permanent organization to look out for the world interests in the mechanical sciences. Thus, IUTAM, theInternational Unionof Theor- ical and Applied Mechanics, was formed on September 26, 1946. In 1947 IUTAM became a member of ICSU, the International Council of Sci- ti?c Unions, itself founded in 1931. The highest authority of IUTAMis the General Assembly, with delegates from the Adhering Organizations, each of which is a?liated with a national learned society in a given country. Scienti?cProgram Contemporary mechanics poses both, the fundamental problems from the area of pure science, and its strong links with modern technology.