Jeffrey Sachs is an American economist and public policy expert known for his work on global economic development, poverty alleviation, and sustainable development. He is a professor at Columbia University and has served as a special advisor to the United Nations on various initiatives, including the Millennium Development Goals. Sachs gained prominence in the 1990s for his role in advising countries transitioning from communism to market economies. He has authored several books and articles, focusing on issues such as economic reform, environmental sustainability, and the fight against climate change. His work emphasizes the importance of integrating economic policies with social and environmental considerations.