Originally published in 1975, for the previous twenty years or so researchers had been working steadily, accumulating data relating to the physiological status of patients suffering from various psychiatric disorders. Their studies came under the broad heading of clinical psychophysiology – the study of physiological measures in psychiatric patients. This field included the application not only of neurophysiological information, which was of particular relevance in the study of mental illness, but also of other sub-disciplines of physiology, such as endocrinology and cardio-vascular physiology.In this text Dr Lader, a distinguished research psychiatrist who had carried out many psychophysiological studies of anxiety and depression, provides an introduction in depth to this complex topic. He reviews the background to the discipline, and its techniques, and gives an account of the main psychophysiological findings in groups of patients suffering from anxiety, depression, schizophrenia and various other psychiatric complaints. Intended in particular for psychiatrists and clinical psychologists in training at the time, this study had important implications for related fields, and for doctors in general practice. Today it can be read in its historical context.