Book excerpt: The New York area's premier forensic psychologist--the expert prosecutors turn to when a defendant claims insanity--looks back over her most celebrated cases to deliver a no-holds-barred critique of recent insanity defense abuses. Zeroing in on cases such as the Menendez brothers and Jeffrey Dahmer, Kirwin shows how unscrupulous defense attorneys and overzealous prosecutors have perverted the true purpose of the insanity defense. of photos.