Invasive species are widely recognized as a major threat to marine biodiversity. This important book synthesizes current information about invasive seaweeds and human responses to them, and considers seaweed invasions in the context of broader thinking about invasion ecology. This includes addressing legal frameworks for regulatory control, practical means to track and respond to invasive seaweeds in the field, as well as the ecology of invasions. The result is both a valuable multidisciplinary synthesis of work to date, and a pointer to future challenges and priorities.