A scientist explores the intricate “ocean engine”—the physics that drive Earth’s interconnected seas and why it is crucial to our survival. Helen Czerski’s The Blue Machine takes readers on a journey from the deep ocean floor to coral reefs, estuaries, coastal waters, and Arctic ice floes, illustrating how sunlight powers a single global engine that moves energy, water, life, and materials across the planet. Through stories of history, culture, and marine life, she explains how temperature, salinity, gravity, and tectonic movement work together to sustain ecosystems from plankton to whales. Czerski warns that this life-supporting system now faces urgent threats, and understanding the ocean’s workings is key to protecting our planet’s blue machine.