Daniel J. Jacob is the Vasco McCoy Family Professor of Atmospheric Chemistry and Environmental Engineering at Harvard University, Massachusetts. He received his PhD from the California Institute of Technology in 1985 and joined the Harvard University faculty in 1987. His research covers a wide range of topics in atmospheric composition, with focus on model development and applications to interpretation of observations. Among his professional honors are the NASA Distinguished Public Service Medal (2003), the American Geophysical Union Macelwane Medal (1994) and the Packard Fellowship for Science and Engineering (1989). Jacob has published over 350 research papers and trained over 80 PhD students and postdocs in atmospheric chemistry modeling over the course of his career.