<div> Algae have long been used as a food and also in the production of food ingredients. There is now increasing interest in their exploitation as sources of bioactive compounds for use in functional foods and nutraceuticals. The expert contributors review key topics in these areas, encompassing both macroalgae (seaweeds) and microalgae.<BR> <br> After a chapter introducing the concept of algae as a source of biologically active ingredients for the formulation of functional foods and nutraceuticals, part one explores the structure and occurrence of the major algal components. It discusses the chemical structures of algal polysaccharides, algal lipids, fatty acids and sterols, algal proteins, phlorotannins, and pigments and minor compounds. Part two highlights biological properties of algae and algal components and includes chapters on the antioxidant properties of algal components, anticancer agents derived from marine algae, anti-obesity and anti-diabetic activities of algae, and algae and cardiovascular health. The third section focuses on the extraction of compounds and fractions from algae and covers conventional and alternative technologies for the production of algal polysaccharids, such as enzymatic extraction, subcritical water extraction and supercritical CO2 extraction of bioactives from algae, and ultrasonic- and microwave-assisted extraction and modification of algal components. Finally, the conclusion explores applications of algae and algal components in foods, functional foods and nutraceuticals including the design of healthier foods and beverages containing whole algae, prebiotic properties of algae and algae-supplemented products, algal hydrocolloids for the production and delivery of probiotic bacteria, and cosmeceuticals from algae.</div>