The insanity defense debate has come full circle, again. The current round began when John Hinckley opened fire; in 1843, it was Daniel M'Naghten who pulled the trigger; the "acts" of both would-be "insanity acquittees" provoked the press, the populace, a President, and a Queen to expressions of outrage, and triggered Congress, the House of Lords, judges, jurists, psychologists, and psychiatrists to debate this most maddening matter. "Insanity" -which has historically been surrounded by defenses, defen- ders, and detractors-found itself once again under siege, on trial, and undergoing...