This second volume of Research Methods in Neurochemistry develops themes featured in the first volume and also introduces new approaches to neurochemical methodology. A further chapter on cell separation tech- niques seemed justified in view of its general importance to the study of neurone-glia relationships and the complexity of the methodological prob- lems involved. Biogenic amines also receive more attention in chapters on the assay of monoamine oxidase, catechol-o-methyltransferase and pineal indoles; subcellular fractionation features again in chapters on methods for the isolation and study of brain mitochondria and synaptic vesicles. Among the new subjects dealt with in this volume, the chapter on cell culture per- haps represents the most distinctive departure from the themes of the first volume. Culture of neural tissue and cells has, of course, been studied by neurobiologists for several decades, but it is only recently that the neuro- chemical potential of this approach has begun to be exploited. We believe that neurochemists wishing to enter this field will find Dr. Herschman's extensive treatment of the subject in this volume of particular interest. Readers familiar with Volume 1 will note that the balance of subjects in this volume is broadly similar. Thus it has proved convenient to group the chapters under the same section headings as before, with the inclusion of chapters on amino acids in Section IV.