Social and technological transformations for sustainable development often involve trade-offs, value conflicts and hard choices, which we are confronted with as individuals or groups. Tough decisions have to be made on complex issues fraught with uncertainties and uncomfortable knowledge. This set of seven public lectures is designed to equip for better understanding and acting in the face of complexity and interdependencies of the natural and social world. All lectures are organised to speak to three key dimensions of sustainability challenges:•How do we know what are the relevant facts and why should we accept their advice?•Who are the various ‘we’, and how can we take account of divergent interests and expertise?•How can we better manage complexities emerging from interconnection of the social and material phenomena, local and global interconnectedness, interdependencies and inequalities and reconcile tensions and contradictions?The first three lectures address in turn the topics of water quality and equity; the requisites of sustainable farm systems, and sustainable energy production and use. The subsequent four lectures explore models to conceptualise socio-technological transitions for sustainable development, tools to handle value conflicts and reveal values underlying diverse claims on science, approaches to legitimating knowledge that might become subject to controversy, and the changing role of science in society – or scientists and citizens having to take a stance on competing claims to science.