This book is about the arachidonic acid cascade, its biochemistry, its pharmacology, and its roles in signal transduction. Arachidonic acid may serve as an intracellular second messenger in many cell types, as well as precursor for biologically active molecules such as the eicosanoids (a family of oxygenated metabolites that may act as second messengers or as local mediators), and anandamide (an endogenous cannabinoid substance). Dysfunctions in the arachidonic acid cascade underlie a number of serious pathological conditions, making these biochemical pathways the target for drugs of clinical value.