The new Mental Act, amending the 1983 Act, was passed in 2007 and came into operation only this year. The new Mental Capacity Act was passed in 2005 and came into operation in 2007. Together they represent major changes in how mental health professionals should care for their patients, reflecting the shift from institutional to community care that has taken place since 1983. Crucially the new Mental Health Act redefines mental disorder and removes the ‘treatability’ test. These and other changes have caused great controversy, but now the new legislation is in place there is a need to understand what it means for the individual practitioner when making decisions about the care of individual patients. Essential Mental Health Law is the practical guide that will provide this understanding. Neutral on the wrongs and rights of the new legislation, it sets the controversy on one side to help psychiatrists, clinical psychologists, mental health nurses and social workers with the day to day application of the law in clinical practice. Non-specialist lawyers will also find it invaluable.