The central question of my scientific work has been, what is and ought to be the human use of the earth? It has been pursued collectively, with mentor, colleagues, students, and friends as a set of research questions related to hazards, hunger, and sustainable development. Regarding hazard, I tried to understand why people persist in occupying areas subject to natural and technological hazards and how adaptation made this possible. An extended stay in Africa to research both environment and development led to new queries. Why does hunger persist amid a world of plenty, and what can be done to end it? Can there be a transition to sustainability that over the next two generations would meet human needs and reduce hunger and poverty while maintaining the essential life support systems of the planet? All three themes and the research methods used to pursue them come together in an emerging sustainability science.