Many processes of change involving population, resources, environment and development are not sustainable. In seeing what to do, normal professionalism and 'first' thinking are part of the problem. The concept of secure and sustainable livelihoods for the very poor and poor is powerful. Developing this approach, the thinking of professionals about environment and development and that of poor people about livelihoods can be combined as a sustainable livelihood thinking. The potential for applying this in resource-poor environments has been underestimated. Analytical implications include the concept of sustainable livelihood intensity. Practical implications include secure rights for the poor to use and sell assets, and a new professionalism which starts not with things, but with people, putting first those who are poorer.