Mental illness is a highly controversial and contested field, informed by the ideas and research of academics and practitioners working in psychiatry, psychology, pharmacology, sociology, genetics and the neurosciences. This book brings clarity to a complex field, exploring core issues ranging from debates about the way the concept has been developed and expanded over time to controversies over the causes of mental illness. The author evaluates critiques of the concept of mental illness and of the way its expanding boundaries now define a far wider range of mental states, experiences and activities as pathological. Arguing that these boundaries need to be restricted, the author contends that many of the phenomena identified as mental illness are normal reactions to life's difficulties and that, while individuals may need support, it is not appropriate or helpful for such phenomena to be treated as indicative of mental disorder. Other important topics covered include the way mental illness is measured, its distribution across populations and over time, and the different types of care provided for those with identified mental illness. Mental Illness will prove invaluable for intending practitioners in medicine, psychiatry, mental health nursing, social work, and clinical and health psychology, as well as for students in psychology, sociology and the health sciences.