This fully revised and expanded edition of Sea Urchins provides a wide-ranging understanding of the biology and ecology of this key component of the world's oceans. Coverage includes reproduction, metabolism, endocrinology, larval ecology, growth, digestion, carotenoids, disease and nutrition. Other chapters consider the ecology of individual species that are of major importance ecologically and economically, including species from Japan, New Zealand, Australia, Europe, North America, South America and Africa. In addition, six new contributions in areas such as immunology, digestive systems and community ecology inform readers on key recent developments and insights from the literature.Sea urchins are ecologically important and often greatly affect marine communities. Because they have an excellent fossil record, they are also of interest to paleontologists. Research on sea urchins has increased in recent years, stimulated first by recognition of their ecological importance and subsequently their economic importance. Scientists around the world are actively investigating their potential for aquaculture and fisheries, and their value as model systems for investigations in developmental biology continues to increase.