Tellus Institute was established in 1976 as an interdisciplinary not-for-profit research and policy organization. The times were propitious for a young institute bringing fresh thinking and scientific rigor to environmental and social challenges, and it grew rapidly. Over the years, we conducted 3,500 projects throughout the world, becoming an international leader in resource and environmental strategies and helping shape the embryonic field of sustainable development. Tellus has worked at every geographic level – global, regional, national, local, and enterprise – bringing both vision and analytic rigor to fashioning strategies, policies, and decision-support tools. Our projects have been distinguished by an integrated perspective in order to illuminate the important linkages across spatial scales and among environmental, social, and economic dimensions of development. Key foci have included energy, water, sustainable communities, corporate social responsibility, and climate change. The Institute’s wide diversity of sponsors – foundations, government agencies, multilateral organizations, civil society organizations, and business – reflects the range of our program. Tellus has partnered with hundreds of organizations, most notably the Stockholm Environmental Institute with which we coordinated programs for nearly two decades. In 2005, Tellus entered a new phase, consolidating its programs to address the grand challenge of this century: a Great Transition to a sustainable, just, and livable global civilization. To attain this vision, the world must navigate toward ways of producing, consuming, and living that balance the rights of people today, future generations, and the wider community of life. The prospects for such a transition rest with the ascendance of new values, a planetary consciousness, and a sense of global citizenship. These aims will lie at the heart of the Institute’s program of research, education, and network-building in the coming years.