The revolution in molecular genetics has given rise to the heady optimism that biology will soon explain all disturbances of mind and behaviour. In this important and necessary book, Julian Leff, a world-leading psychiatrist, counters this reductionist stance. Instead he emphasises what is known about the psychological, social and cultural factors underlying mental illness. In doing so, he addresses many serious and urgent questions. What exactly is the difference between sadness and depression? What are the difficulties in categorising psychiatric conditions? How are psychiatric diagnoses made in the first place? What is the influence of emotional relationships on psychiatric conditions? Is there a link between schizophrenia and socio-economic deprivation? How do public attitudes to mental illness affect choice of treatment? And, finally, what does this tell us about the cultural causes of mental illness?