This book addresses why just about everything that we experience on Earth depends upon the ocean circulation, the movement of the ocean water. Intended for a general lay-person audience, or as a non-science major undergraduate text, the book explains (in a non-mathematical manner) how the ocean circulation and the ocean interactions with the atmosphere provides the basic underpinnings for global climate and ecology. It then launches into more specific topics of societal relevance (e.g., how the coastal ocean and estuaries work, sea level variations, ocean waves and extreme tsunamis, hurricane storm surge and wave damage, how ocean temperatures change seasonally, harmful algal blooms, alternative energy potential and fish recruitment). Whereas some of these applications have a Florida, USA emphasis, all of them are equally applicable to coastal regions elsewhere.