Water exists in many places in the universe and may be the principal element for life on Earth's surface. Its presence is a hallmark of the habitable zones for living things (humans, animals, and plants). About 70 percent of Earth's surface is covered with water, but only about 1 percent of the water on Earth's surface is usable by living things (groundwater and surface water). Water has several properties that make it unique among compounds and make it possible for all forms of known life to function. Water is a uniquely wonderful substance on Earth that naturally occurs in three different states: solid, liquid, and gaseous. All living things depend on water. When water resources are polluted, all forms of life are threatened. Water scarcity is a function of cultural activities and human civilization. It is very important to highlight water's pivotal role as the essential ingredient for life and to develop a comprehensive framework for creating water-resource policies to manage water resources. This book includes photographs of water and life to demonstrate to the reader water's properties and water's effects on life.