Because of the biological origin of many siliceous deposits, their geochemical transformation in the marine environment, and their occurrence in many formations around the world, oceanographers, paleontologists, geologists, geochemists, and sedimentologists are working closely together to trace the evolution of such deposits. In this book, leading experts from all of these disciplines present new data on fine-grained deposits such as chert, primarily of the Tethys region but also of the Pacific. Much of the information presented here was gathered recently in coordinated international research projects and is made available in English for the first time.