Marine plants such as algae (blue-green algae and seaweeds), seagrasses, mangrove plants, salt-tolerant or salt-loving plants (halophytes) and coastal sand dune plants are known to generate approximately 70% of oxygen on earth, and help regulate oxygen in the atmosphere. These plants are potential sources of nutrients and are also considered valuable for the development of new drugs owing to their unique bioactive compounds. This book provides the taxonomy, common name, global distribution, habitat, diagnostic features and pharmaceutical compounds (along with their activities) of 400 species of marine plants, accompanied by high quality illustrations.