Meet Marie Tharp (1920-2006), the first person to map the Earth's underwater mountain ridge, in this inspiring picture book biography from the author of Shark Lady. From a young age, Marie Tharp loved watching the world. She loved solving problems. And she loved pushing the limits of what girls and women were expected to do and be. In the mid-twentieth century, women were not welcome in the sciences, but Marie was tenacious. She got a job in a laboratory at Cambridge University, New York. But then she faced another barrior: women were not allowed on the research ships (they were considered bad luck on boats). So instead, Marie stayed back and dove deep into the data her colleagues recorded. She mapped point after point and slowly revealed a deep rift valley in the ocean floor. At first the scientific community refused to believe her, but her evidence was irrefutable. She proved to the world that her research was correct. The mid-ocean ridge that Marie discovered is the single largest geographic feature on the planet, and she mapped it all from her small, cramped office.