Dinoflagellates are important primary producers, symbionts and, at the same time, heterotrophic consumers and parasites. The species composition in benthic habitats is quite distinct from planktonic habitats. This book is a fundamental contribution to improving the monitoring of benthic dinoflagellates worldwide: 242 species in 63 genera are presented, illustrated with more than 240 color images, about 250 electron micrographs and more than 330 drawings.