Legal norms adopted by the Federal courts since 1954 to the passage of the 1984 Insanity Defense Act are examined, with a focus on changes in the standards and burdens of proof. The role of expert witnesses and the jury in defense-of-insanity trials is examined with particular attention to issues arising in trials involving assassination or attempted assassination of national leaders. Results of a national survey highlight variations in the views of the insanity defense and related issues held by judges, attorneys, and mental health professionals. The movement to abolish the insanity defense and replace it with an alternative verdict of 'guilty but mentally ill' is reviewed, and policies of States that have abolished or diminished the insanity defense as reflected in statutory provisions of European, Asian, African, and Latin American countries. The treatment of crime, criminal responsibility, and the insanity defense in fiction and theater also is presented. A State-by-State listing of insanity defense standards, burdens of proof, and verdict forms is appended. Chapter notes and tables and a 24-item bibliography.