This edited book provides a comprehensive and a reliable source of information on all major areas of diatom research. It addresses research advances in the key areas of diatom biology, morphology, systematics, phylogeny and ecology along with their interdisciplinary applications. Diatoms are the world most diverse group of algae populating the freshwater and marine ecosystems of the world. They are unicellular, photosynthetic, eukaryotes having ornate silicified cell walls. Diatoms contribute around 25% of annual global carbon fixation, which is more than all of the terrestrial rainforests combined. Diatoms underpin major aquatic food webs and drive global biogeochemical cycles and have several ecological and interdisciplinary applications. This book targets a wide range of audience including researchers, academicians, teachers and students of varied disciplines such as biology, environmental sciences, ecology, evolution, nanotechnology and other related disciplines. It is useful read for beginners as well as advanced researchers.