This book aims at providing students and researchers an advanced integrative overview on zooplankton ecology, covering marine and freshwater organisms, from microscopic phagotrophic protists, to macro-jellyfishes and active fish larvae. The first book section addresses zooplanktonic organisms and processes, the second section is devoted to zooplankton spatial and temporal distribution patterns and trophic dynamics, and the final section is dedicated to emergent methodological approaches (e.g., omics). Book chapters include comprehensive synthesis, observational and manipulative studies, and sediment-based analysis, a vibrant imprint of benthic-pelagic coupling and ecosystem connectivity. Most chapters also address the impacts of anticipated environmental changes (e.g., warming, acidification).