Easter Island, a World Heritage Site is still, after over 50 years since Jacques Cousteau's work on the island, a fascinating area to explore and learn about a culture that has only remnants remaining, while documenting a marine ecology still mostly unknown. This text presents the research results from three years of interdisciplinary expeditions to Easter Island. The primary objectives were to investigate the effects of human population growth on the ecology of the island and to discover whether any dramatic climatic changes such as a prolonged El Nino could have disrupted the island's fragile ecosystem. The interdisciplinary scientific team were mainly researching the paleontology, archaeology, climatology and geophysics of the island. This book brings together the results of the three expeditions, identifies new areas of research, and hopefully will continue to inspire aspiring scientists to revisit this island to explore and demystify this timeless enigma of human history.