This series is a collection of methods and techniques for assaying substances of biological importance. The general method of presentation in this as in the other volumes entails a discussion of background and early work, isolation of material from tissues and fluids, evaluation of methods, and details of recommended procedures. The author of each chapter is given great freedom in the manner of presenting his material to avoid a stereotyped series of chapters. Volume 7 contains chapters on immunoelectrophoretic analysis, analysis of basic nitrogenous compounds of toxicological importance, spectrophotometry of translucent biological materials, determination of inositol, ethanolamine, and serine in lipids, the assay of lipoprotein lipase, determination of creatinine and related guanidinium compounds, the determination of ethyl alcohol in blood and tissues, and determination of heparin. In volume 8 are discussions of procedures for fatty acid determinations by gas-liquid chromatography, for luciferin and luciferase, for enzymic analysis of steroid hormones,