Seaweeds are known for their rich bioactive compounds, which promote health in human beings and are good for the ecosystem as well. They are also natural resources that are a major source of raw material for different industries. There are still undiscovered and unexploited compounds synthesized by seaweeds that may have potential applications in the pharmaceutical, nutraceutical, food, and cosmetics industries. This book serves as a comprehensive knowledge source for the predominant roles of seaweeds in various sectors, particularly in the areas of health, environment, and agriculture. It explores the diverse biodiversity aspects of seaweeds and their derivatives. The book critically reviews the present industrial challenges to investigate the novel compounds synthesized by seaweeds and their unique characteristics and benefits. The volume covers the various biodiversity attributes of tropical seaweeds, their cultivation and bioactive compounds, and the diverse agricultural and biomedical applications of new seaweed derivatives. The authors also discuss the current challenges, emerging markets, and latest developments in extracting the useful biomolecules from seaweeds as well as the role of seaweeds in food security and environmental mitigation. With chapters written by experts and professionals in the field, this volume, Seaweed Biotechnology: Biodiversity and Biotechnology of Seaweeds and Their Applications, provides a deep understanding of the biodiversity of seaweeds around the world and their industrial, biomedical, and environmental applications.