A small part of the scientific community is seeking hard to enhance the contribution of science, knowledge and capacity building to environmentally sustainable and socially fair human development around the world. Many researchers over the globe share the same commitment – anchored in concerns for the human condition. They believe that science and research can and have influenced sustainability. Therefore their main goals are to seek and build up knowledge, know-how and capacity that might help to feed, nurture, house, educate and employ the world's growing human population while conserving its basic life support systems and biodiversity. They undertake projects, that are essentially integrative, and they try to connect the natural, social and engineering sciences, environment and development of communities, multiple stakeholders, geographic and temporal scales. More generally, scientists engaged in sustainable development are bridging the worlds of knowledge and action. This pro-active, heavily ethics- and wisdom-based "science for sustainability" can be seen as the conclusion of all dialogues and discussions amongst scientists at the World Summit on Sustainable Development (WSSD) 2002 in Johannesburg. The "Plan of Implementation" after WSSD will be based on political will, practical steps and partnerships with time-bound actions. Several "means of implementation" are going to be proofed and initiated: finance, trade, transfer of environmentally sound technology, and, last but not least, science and capacity building.