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.

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.

The IUTAM Symposium on "Discrete Structural Optimization" was devoted to discuss optimization problems for which design va riables may not be sought among continuous sets. Optimum sizing from lists of available profiles, segmentation; as well as allocation and number of supports, sensors or actuators, are good exam ples of such problems for which design variables may be chosen only from finite sets. The above problems are having not only important practical applications. They are also inspiring scienti fic research in the field of discrete applied mathematics. Among them are controlled enumeration methods, subgradient approach, genetic programming, multicriteria optimization, neural nets etc. Along with its tradition of promoting and supporting new im portant fields of research in mechanics and its application, General Assembly of IUTAM decided in 1990 to support the Sumposium. It is worthy to note that this is the second IUTAM Symposium on structural optimization, organized in Poland. The first one was held in Warsaw twenty years ago and was organized by Profe ssors Sawczuk and Mroz. It was devoted mostly to problems with continuous design variables. The Symposium which gathered 40 participants from 12 coun tries was sponsored by several institutions listed below. However support by IUTAM should be specially appreciated. It helped se veral scientists to contribute to the Symposium which other way wouldn't attend the meeting."