When trying to coax interesting quantum behavior out of a system, we normally view dissipation as a nuisance whose effects should be minimized as much as possible. In this talk, I'll discuss a powerful and seemingly paradoxical approach where dissipation is deliberately harnessed to prepare interesting quantum states and functionalities. I'll focus on recent theory from my group showing how this strategy can be employed in quantum optomechanical systems, where the motion of a “large” mechanical resonator interacts strongly with light via radiation pressure forces. Here, ‘engineered dissipation’ can allow the preparation quantum states of both light and mechanical motion. These ideas have been recently implemented experimentally to prepare non-classical squeezed and entangled states of nanogram-scale mechanical resonators, with the relevant dissipation produced by microwave photons in a superconducting quantum circuit.