A gaggle of rattails and two assfish investigate bait in an image captured by the Caladan Oceanic Five Deeps Expedition. Photo: Tamara Stubbs/Atlantic Productions/DiscoveryIt is said that we know more about the surface of the moon than about the depths of the ocean. That might not be the case for Susan Casey. Across an eventful career Ms. Casey—a former editor in chief of O, the Oprah Magazine—has researched and written books about big waves, great white sharks, dolphins and, in “The Underworld,” the oceanic depths. She dedicates her latest book to “those who love the ocean,” which she clearly does, writing about it with passion, knowledge and insights from personal experience.

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Persons: Tamara Stubbs, Susan Casey, Casey —, O, — Organizations: Atlantic Productions, Oprah