Ibsen is often called the 'father of realism' for his plays that challenged traditional social and moral values. His masterpieces, such as A Doll's House, Hedda Gabler, and Ghosts, dealt with themes of marriage, social hypocrisy, and individual freedom. His work was initially scandalous but eventually transformed world theater, moving it away from melodrama toward serious, psychological exploration. He remains the most performed dramatist in the world after Shakespeare.