In the 1930s, the pioneering Danish scientist Inge Lehmann (1888–1993) made a groundbreaking discovery about the nature of Earth. Analyzing data from earthquakes, she determined that the heart of the planet is a solid inner core. Her discovery overturned the widely accepted theory of the core being fluid, but she trusted her calculations: “If I am right, and I know I am,” she wrote in a letter. A fiercely independent thinker, Lehmann forever changed our understanding of our planet.

If I Am Right, and I Know I Am provides a powerful portrait of an extraordinary woman while guiding readers through the fascinating history of earth science. Hanne Strager tells the story of Lehmann’s life and accomplishments, recounting how she battled inner demons and a mental breakdown and how she overcame pervasive prejudice to forge her own path in a male-dominated scientific world. In Lehmann’s era, women were expected to conform to rigid roles and were discouraged from pursuing serious academic careers. Even as Lehmann became a leading geophysicist, she had to navigate not only gender bias but also the isolation of being a lone woman in an overwhelmingly male field. Strager also follows the traces of an elusive love letter linking Lehmann romantically to another woman. The first biography of Lehmann, this book seamlessly weaves together her personal life and scientific achievements, highlighting her resilience and brilliance.

Hanne Strager is a biologist and acclaimed science writer. Her books include The Killer Whale Journals: Our Love and Fear of Orcas (2023), which received a National Outdoor Book Award. She is the director of exhibitions of The Whale in Norway and was formerly the director of exhibitions at the Natural History Museum of Denmark.