This book provides a multidisciplinary overview of the importance of zooplankton in aquatic ecosystems based on three main core areas: Ecology, Ecotoxicology and Environmental Education. The world of zooplankton is presented starting from the basic aspects of their biology and ecology to the recent scientific advances and technologies, including the interface with multidisciplinary and resources management models. The present and projected challenges from global warming, ocean acidification and anthropogenic pollution are examined in several worldwide case studies. This book will show the readers the potential and importance of these creatures to aquatic wildlife.