Four chapters on schizophrenia and late-life psychosis follow. The first, on MRI, is encyclopedic (the table of individual studies is 24 pages long), and at the end the authors indicate that the two robust findings are lateral ventricular enlargement and temporal and medial temporal lobe volume reduction. MRS studies in schizophrenia are reviewed next; there were only a dozen or so through 1995. These have shown reduced N-acetyl aspartate in the temporal lobes, evidence of membrane alterations (phosphomonoesters and phosphodiesters), and possible alterations in energy metabolism (nucleotide triphosphates). The third chapter reviews PET studies of cerebral metabolism and blood flow, of which there are many, like the MRI studies. The authors conclude that the PET results on anterior-posterior and laterality differences in FDG uptake and blood flow, including those with cognitive activation, are equivocal. In this chapter, as in most of the others, potential sources of variability are mentioned, including patient selection, sample size, demographic factors, image acquisition technique and anatomical coregistration, and cognitive activation paradigms. The chapter on late-life psychosis covers primarily morphologic studies and comes to conclusions similar to those for earlier-age schizophrenia, i.e., ventricular enlargement and temporal lobe volume reduction. Additionally, increased thalamic volume and a greater number of discrete gray and white matter lesions have been described in elderly psychotic patients.