Book excerpt: Clinical Biochemistry: Contemporary Theories and Techniques, Volume 2 is a collection of papers that deals with coagulation chemistry, inborn errors of metabolism (IEM), and the biochemistry of aging. One paper explains the biochemistry and clinical importance of lipoprotein-X (LP-X) as a marker for obstructive jaundice and also as a pointer in the deficiency of lecithin-cholesterol acyltransferase (LCAT), a rare inborn error of metabolism. Another paper presents guidelines in determining radioimmunoassay that are used, for example, in identifying enzymes produced by various malignant lesions. One paper reviews the basic molecular events and interactions involved in the blood clotting process and its related systems. To determine inborn errors of metabolism, the investigator can use screening techniques, prenatal diagnosis or therapy, and laboratory procedures related to IEM. To correct errors at the gene level, transgenosis and genetic engineering use recombinant DNA research techniques involving the introduction of a foreign DNA into the host cell. Some examples of IEM are phenylketonuria and hyperphenylalaninemia without PKU. This collection can prove useful for the clinical chemists, endocrinologists, internists, medical practitioners, and investigators involved in research on biochemistry.