Tracing the path of water in space has been one of humanity's oldest dreams. For centuries, venturing beyond the seas, lakes, and oceans to search for traces of life in the cosmos has raised some of the most thrilling and profound questions in science. This book narrates the journey of discovery into the depths of the universe, exploring the new frontiers revealed by the search for water beyond our planet. Water in the cosmos is not just a simple chemical compound; it plays a crucial role as a key to unlocking the mysteries of life. From the icy poles of Mars to Europa, Jupiter's moon, from the frozen surface of Saturn's Enceladus to Titan's methane seas, many celestial bodies signal the presence of water. In all its forms, whether beneath the surface or in vast oceans, water in space beckons scientists and astrobiologists to one of the greatest questions: Could life lie beneath these deep oceans? In this book, we aim to follow the traces of water found beyond our planet, venturing into the farthest corners of our solar system. Along the way, we explore the potential for life beneath these alien oceans, the chemical structure of water, its geophysical properties, and its astrobiological significance. Each chapter presents insights into the latest scientific research and the evolving methods used to uncover the secrets of these cosmic water reservoirs. While delving into the latest scientific advancements and deepening our understanding of space exploration, this book also sheds light on the exciting possibilities for future missions. The discovery of water, especially beneath the surfaces of distant moons, could not only reveal evidence of extraterrestrial life but also offer new insights into humanity's own origins. Water, as the essence of life, could be a key to unlocking new forms of life, not just on Earth but across the universe. As you embark on this journey of discovery with us, we invite you to venture deeper into the unknown, taking yet another step toward understanding the vast potential that lies ahead. The mysteries of water may hold the answers to questions far beyond our current reach, and perhaps the promise of new worlds and civilizations awaits us.