AFTER CONSIDERATION OF SOME GENERAL ISSUES SURROUNDING THE INSANITY DEFENSE (PURPOSE, FUNCTION, SIGNIFICANCE), THE AUTHOR REVIEWS THE VARIOUS TESTS OF INSANITY OR CRIMINAL RESPONSIBILITY THAT HAVE BEEN USED, INCLUDING THE M'NAUGHTON KNOWLEDGE OF RIGHT AND WRONG TEST, THE IRRESISTIBLE IMPULSE TEST, THE DURHAM PRODUCT OF MENTAL DISEASE OR DEFECT TEST, THE AMERICAN LAW INSTITUTE'S MODEL PENAL CODE TEST OF MENTAL DISEASE OR DEFECT EXCLUDING RESPONSIBILITY, AND THE JUSTLY RESPONSIBLE TEST. AN OVERVIEW IS THEN PRESENTED OF THE PROCEDURAL DISADVANTAGES TO THE DEFENDANT RAISING THE INSANITY DEFENSE. SOME OF THE ISSUES DISCUSSED ARE THE BURDEN OF PROOF, THE BIFURCATED TRIAL CONCEPT, THE QUESTION OF EXPERT (PSYCHIATRIC) ASSISTANCE, EXAMINATION, AND TESTIMONY. OTHER TOPICS EXAMINED IN THIS REPORT INCLUDE THE DISPOSITION (CIVIL COMMITMENT) OF PERSONS ACQUITTED BY REASON OF INSANITY AND THE USE OF THE DOCTRINE OF DIMINISHED RESPONSIBILITY. THE AUTHOR PROPOSES THAT THE INSANITY DEFENSE BE RETAINED AND EXPANDED TO INCLUDE THOSE INDIVIDUALS WHOM 'AN ENLIGHTENED SOCIETY' WOULD DEFINE AS NOT CRIMINALLY RESPONSIBLE. HE ALSO SUGGESTS THAT WHENEVER A CRIME REQUIRES AS A NECESSARY ELEMENT THAT THE ACT BE COMMITTED WITH A PARTICULAR MENTAL STATE, EVIDENCE OF A DEFENDANT'S MENTAL ABNORMALITY SHOULD BE ADMISSIBLE TO PROVE HE LACKED THE REQUIRED MENTAL STATE, SEPARATE AND APART FROM THE INSANITY DEFENSE. A THIRD RECOMMENDATION IS FOR LEGISLATION AIMED NOT SOLELY AT REVISING THE TECHNICAL LANGUAGE UTILIZED IN THE VARIOUS FORMULATIONS OF THE INSANITY TEST, BUT ALSO AT INSURING FAIRNESS IN THE PROCEDURES FOR RAISING AND DETERMINING THE DEFENSE AND REFORM IN THE SYSTEM OF DISPOSING OF THOSE WHO SUCCESSFULLY ASSERT THE DEFENSE. THE AUTHOR INSISTS THAT A REQUIREMENT THAT AN INDIVIDUAL SUCCESSFULLY PLEADING THE INSANITY DEFENSE BE COMMITTED TO A MAXIMUM SECURITY FACILITY FOR AN INDEFINITE TIME DESTROYS ANY JUSTIFICATION FOR THE DEFENSE AND REDUCES ITS SIGNIFICANCE TO LESS THAN DE MINIMUS. (AUTHOR ABSTRACT MODIFIED)