This monograph will put the biogenic marine lipids of many organisms in perspective. Up to 100 years ago, fish and shellfish were frequent and major components of our "western" diet. In search of progress and convenience, we have given up many such foods in favor of those produced by "agribusiness" interests. There are different viewpoints on the merits of the marine omage-3 fatty acids and of the terrestrial omega-6 fatty acids in human nutrition, and every individual may have different needs. This monograph should help researchers relate these basic building blocks of lipids in the fascinating world of marine organisms to our contemporary interest in human biochemistry, nutrition, and health.