Sea urchins are a major component of the world ocean. They are important ecologically and often greatly affect marine communities. They have an excellent fossil record and consequently are of interest to paleontologists. Research has increased in recent years stimulated first by a recognition of their ecological importance and then because of their economic importance. Scientists around the world are actively investigating their potential for aquaculture. This book is designed to provide a broad understanding of the biology and ecology of sea urchins. Synthetic chapters consider biology of sea urchins as a whole to give a broad view. The topics of these chapters include reproduction, metabolism, endocrinology, larval ecology, growth, digestion, carotenoids, disease and nutrition. Subsequent chapters consider the ecology of individual species that are of major importance ecologically and economically. These include species from Japan, New Zealand, Australia, Europe, North America, South America and Africa.