Since 1970, the Caribbean has lost half of its coral reefs, an ominous and accelerating phenomenon that extends around the world. Today's remaining coral reefs - still a source of endless discovery and mystery for scientists - are at risk of disappearing by century's end. Beyond the unfathomable heartbreak of the loss of such exquisite beauty from the earth's surface, coral's loss represents the annual loss of billions of dollars from the global economy and the end of a way of life for billions that depend on these ecosystems. Marine scientist and conservation leader David E. Guggenheim has had a front-row seat to this disaster. But when he began a new chapter of his career in Cuba, he found something completely unexpected: hope. After years and years of watching reefs deteriorate, Guggenheim was astonished to come face-to-face with Cuba's remarkably healthy coral reefs overflowing with fish and other life - ocean ecosystems that appear healthier than those he first encountered as a teenager more than four decades prior. Living Time Machine reveals the hidden potential that Cuba's reefs may contain for the reefs of the world. Which begs the question: why are Cuba's ocean waters so healthy? The answer is deeply intertwined with the country's extraordinary and singularly unique history, from its dramatic political past to its world-class environmental protections influenced by an unlikely partner, Captain Jacques Cousteau. The result is that while the past 60 years have seen the worst decline in ocean health in human history, Cuba's oceans and coral reefs remain remarkably healthy, a living laboratory never-before-seen by this generation of scientists. The author's account includes interviews with colleagues, scientists, policymakers, and his own decades-long experience as an American working in Cuba with local marine scientists to study and protect its coastal waters and coral reef ecosystems. Living Time Machine tells the story of the demise of the world's ocean ecosystems, the hard work of those desperately trying to save it, and an unexpected beacon of hope from an island full of mystery and surprises.