Psychiatry is a discipline that crosses many frontiers, involving a know ledge of the anatomy, physiology and biochemistry of the nervous system, of general medicine, of sociology, of psychology, of the law and of all those subjects which comprise the behavioural sciences. Moreover, in the field of psychiatry the explosion of knowledge has led to an increase in special ization in sub-disciplines. To all those interested in psychiatry this diversity causes real problems. They may have to consult a wide variety of sources before finding the answer to what may be in fact a relatively simple...