While nanotechnology initially, promising fulfilling high expectations, had raised little ethical awareness only, this situation changed radically in the course of possible horror scenarios involving self-organizing nanotechnology. Early ethical consideration of nanotechnology focused on proceeding responsibly in this tension between paradise-like expectations and dystopian stories. Nanoethics quickly developed into an international scholars’ movement contributing a lot to public debate. Beyond this more futuristic debate, a second, more down-to-earth risk debate on nanotechnology emerged. It focused on whether synthetic nanomaterials could cause harm to health and the environment with the precautionary principle having been a major issue of ethical debate. Concerned groups put nanotechnology in close proximity to technologies that many see as highly problematic, such as nuclear technology, and drew an analogy with the asbestos story. In the meantime, ambitious research programs on environmental, health, and safety issues of nanotechnology have been conducted, providing much better knowledge of possible unintended side effects. In the meantime, the more speculative branch of nanoethics, considering, for example, human enhancement and immortality, migrated to other fields such as the convergence technologies, synthetic biology, and artificial intelligence (AI). The more “down-to-earth” reflections on nanoparticle risks, equity, and sustainable development became integral parts of existing regimes of deliberation and regulation. In this way, the ethical aspects moved into familiar fields of the ethics of technology and risk ethics and became “normalized.” Therefore, it seems fair to say that we have witnessed the rise and fall of nanoethics over the last 20 years. This story provided the ethics of new and emerging technologies and the approach of responsible research and development with a rich legacy.