The scale of investment in quantum computation, simulation and sensing is growing at a tantalizing pace. Harnessing the nanoscale to engineer useful quantum effects is a transformative capability of huge relevance to industries and governments. By summarizing the current state and the future directions of quantum nanoscience, a review defining quantum nanoscience published in Nature Nanotechnology this week will help investors and funding agencies make informed decisions on how and why to participate in the quantum technology revolution.