Carl Wunsch, the Cecil and Ida Green Professor Emeritus of Physical Oceanography in MIT's Department of Earth, Atmospheric and Planetary Sciences (EAPS), is at the heart of many of the major advances in modern physical oceanography. The World Ocean Circulation Experiment, satellite altimetry, acoustic tomography, and Estimating the Circulation and Climate of the Ocean: all are hard to imagine without Wunsch's involvement. In this extended interview, Wunsch tells Michael White, climate science editor for Nature magazine and Forecast producer, about these and many other aspects of his decades of work in the field. Along the way, Wunsch describes growing up in Brooklyn, Henry Stommel’s sprawling legacy, the sometimes intense conflicts within the community, the problems of working in a data-poor field, and the role of personality in making, or stalling a career. It’s a one-stop history of the field, and a deeply personal insight into how major science questions are conceptualized and addressed.