Fatty acids play an important role in the barrier function of skin and represent a major source of proinflammatory mediators in inflammatory skin disorders. This book combines the two major functions of fatty acids in skin biology. The first part deals with the biosynthesis of fatty acids in skin with its role in barrier function, as well as the role of dietary fatty acids on skin cell function. The second part deals with skin as a source of proinflammatory eicosanoids, especially with the keratinocyte as a major cellular source. The book finishes with a chapter describing the methods used for quantification of fatty acids and derivatives in skin inflammation.