A for Angry Young Man
That is one epithet which has stuck. When he burst into the scene in the 1970s, this image transformed the industry for good.
It spelt the death knell of reigning superstar Rajesh Khanna and the end of the romantic era. If Anand was Khanna's movie, by Namak Haraam Amitabh had firmly taken over. Grim movies with fighting and sinister villains became more popular after that.