The development of control technology specifically for smart structures and materials has lagged substantially behind that of the base materials, transducers, and embedding techniques. Still, development of smart structures with ever-greater numbers of embedded elements continues, spurred by potential uses that require large arrays of sensors and actuators. For example, rather than implementing a control design that is sensitive to the particular device layout, a densely sampled array allows the controller to optimize the use of sensor information and actuator authority. No control technology suitable for such large arrays exists, however, and this presents a barrier to future applications. In this paper we report on recent progress in developing and demonstrating technology capable of controlling hundreds or thousands of sensors and actuators embedded in the base material. We have dubbed this the `KIKO control problem' (Kilo-Input/Kilo-Output) for smart materials. This paper focuses on a new multiscale/multirate theory of hierarchical design based on the wavelet transform. In the context of this theory, we develop efficient and highly scalable implementations of control systems using multiprocessor architectures. The paper describes our multiscale control approach and presents simulation results on a flexible plate.