Requirements on high efficiency of rotating machinery forces engineers to deal with problems of self-induced vi- brations and balancing of rotors in a serious and scientific manner. The last decade has shown a leap towards the solution of advanced problems of this kind as indicated by the large amount of scientific and engineering papers on rotor dynamics published in international journals. In appreciation of this situation the General Assembly of the International Union of Theoretical and Applied Mecha- nics (IUTAM) at its meeting in Moscow in 1972, acting on a proposal by the Danish...