Effective management of freshwater ecosystems is critical as they have the greatest species diversity per unit area, a larger portion of threatened species, and use of their ecosystem services is generally unsustainable compared with other ecosystems. The loss and degradation of freshwater ecosystems, also referred to in a broad sense as freshwater wetlands, has been documented at site, regional and national levels in many parts of the world, with the most recent analyses showing ongoing decline of species populations and loss of ecosystems. These losses have occurred despite the Ramsar Convention on Wetlands and the Convention on Biological Diversity being signed or ratified by 169 and 196 national governments respectively. Arthington outlines general principles and a range of practices for effective management of specific freshwater ecosystems types, including rivers and estuaries, lakes and reservoirs, peatlands and groundwater-dependent ecosystems. The chapter also presents an overview on the key concepts discussed in this book.