Whether through loss of habitat or cascading community effects, diseases can shape the very nature of the marine environment. Despite their significant impacts, studies of marine diseases have tended to lag behind their terrestrial equivalents, particularly with regards to their ecological effects. However, in recent decades global research focused on marine disease ecology has expanded at an accelerating rate. This is due in part to increases in disease emergence across many taxa, but it can also be attributed to a broader realization that the parasites responsible for disease are themselves important members of marine communities. Understanding their ecological relationships with the environment and their hosts is critical to understanding, conserving, and managing natural and exploited populations, communities, and ecosystems. Courses on marine disease ecology are now starting to emerge and this first textbook in the field will be ideally placed to serve them. Marine Disease Ecology is suitable for graduate students and researchers in the fields of marine disease ecology, aquaculture, fisheries, veterinary science, evolution, and conservation. It will also be of relevance and use to a broader interdisciplinary audience of government agencies, NGOs, and marine resource managers.