We are currently entering a new technological era in which we are able to build systems whose performance is limited by quantum physical effects and in which it may be possible to exploit non-classical phenomena in novel ways. To this end, there has been considerable recent interest in engineering quantum systems and at the heart of this is the development of a quantum control theory dedicated to extending classical control to the quantum domain. Examples already utilizing control of one sort or another include quantum electromechanical systems, quantum dots, Cooper-pair boxes,...