Quantum controllers, featuring quantum coherence and obeying the discontinuous dynamics associated with quantum measurements, imply different constraints and possibilities with respect to their deterministic classical counterparts. After a brief introduction to the typical problems and scenarios that characterise research in quantum control, this talk will highlight a few case studies and developments concerning the optimal control of quantum continuous variables, with specific references to optical systems. We will review cases of open-loop and closed-loop strategies, including both measurement-based and "coherent" feedback control.