Jeffrey Sachs is an economist, university professor, and influential author known for his work in sustainable development. He is the Director of the Center for Sustainable Development at Columbia University and the President of the UN Sustainable Development Solutions Network. His notable roles at the United Nations include serving as a Special Advisor to three different UN Secretaries-General: Kofi Annan, Ban Ki-moon, and António Guterres. He currently serves as an SDG Advocate for the present Secretary-General, focusing on promoting the Sustainable Development Goals. Sachs' work spans global poverty, geopolitics, and public policy, making him a key voice on the frontlines of economic development and international relations.