<jats:title>Abstract</jats:title> <jats:p>This is the last volume of a ten-volume series on The Natural History of the Crustacea. The chapters in this volume synthesize our current understanding of the diverse topics in ecology and conservation of crustaceans. The first section summarizes the role of crustaceans as food for higher trophic levels, as consumers of plant and animal prey, and it examines their contribution to the processing of dead organic material as scavengers and detritivores. The following chapters evaluate how crustaceans modify the structure of ecosystems and the availability of habitat and other resources as bioengineers through, for example, bioturbation. Non-trophic interactions involving crustaceans are synthesized in the following chapters, including parasitism and competition for space and food as well as the importance of crustacean biodiversity and disparity for the structure and functioning of ecosystems. The second section identifies threats to crustaceans in a changing world, such as the effects of habitat loss and fragmentation, global climate change, human land and water use, contaminants, and the impacts of species invasions. The third section of this volume summarizes conservation strategies for endangered crustacean species and habitats and how these strategies can benefit from modern molecular biological technologies and global digital databases. Examples will be given for the successful recovery of crustacean populations in protected areas and how crustaceans are considered in legislative frameworks in, for example, nature conservation and fishery policies. The fourth section addresses the role of crustaceans in human society as a species, as food but also in media and pop culture.</jats:p>