Batman doesn't kill people - it goes against his moral code. His arch nemesis The Joker on the other hand kills at whim, completely devoid of any conscious. In A Death in the Family not only does the Clown Prince of Evil kill Jason Todd's Robin, but he beats him half to death with a crowbar first and then blows him up. It's like nothing we'd ever seen in a Batman comic before - a level of sadistic overkill that was often hinted at in relation to the Joker but never shown. Much of the actual story is throwaway, with Joker working on his tan in Iran and shmoozing with the likes of the Ayatollah but once he committed his maniacal deed A Death in the Family was cemented into Batman legend forever. DC were aware for a while that Jason Todd had become unpopular with their readers so the decision was made to kill him off. What was different about A Death in the Family however is that fans were given the choice as to whether or not they should keep Todd alive. They voted with a resounding NO! This is also another opportunity for Bat fans to see their favourite hero come to blows with the Man of Steel and is one of the first times that the writers ever hinted that Joker may know Batman's secret identity.