A modern mechanical structure must work at high speed and with high precision in space and time, in cooperation with other machines and systems. All this requires accurate dynamic modelling, for instance, recognizing Coriolis and centrifugal forces, strong coupling effects, flexibility of links, large angles articulation. This leads to a motion equation which must be highly nonlinear to describe the reality. r1oreover, work on the manufacturing floor requires coordination between nachines, between each machine and a conveyor, and demands robustness of the controllers against uncertainty in payload, gravity, external perturbations etc. This requires adaptive controllers and system coordination, and perhaps a self organizing structure. The machines become complex, strongly nonlinear and strongly coupled mechanical systems with many degrees of freedom, controlled by sophisticated mathematical programs. The design of such systems needs basic research in Control and System Dynamics, as well as in Decision Making Theory (Dynamic Games), not only in the use of these disciplines, but in their adjustment to the present demand. This in turn generates the need to prepare engineering students for the job by the teaching of more sophisti­ cated techniques in control and Mechanics than those contained in previous curricula. On the other hand, all that was mentioned above regarding the design of machines applies equally well to other presently designed and used mechan­ ical structures or systems.