Ibsen's Doll's House is a commentary on gender roles and their stunting affect on those who attempt to confine themselves within those traditionally accepted roles. Nora, the protagonist, is a woman who has willingly chosen to accept being a 'trophy wife' to her husband Torvald, knowing that it means playing the naive, childish, and helpless counterpart to her husband. Despite having a brain for business and for, frankly, deception and manipulation, she allows her husband to believe her primary thought processes revolve around shopping and being beautiful, because that's what Torvald expects of women.
In exchange for playing this role, Nora expects Torvald to play the role of head of household, caretaker of his charges (including his wife), protector of his domain (which again, includes his wife). One cannot fault Torvald for believing his wife to be devoid of ambition or intelligent thought; he has been conditioned by society to believe this is his role, and encouraged by Nora to relish his part. It is only when a scandal is about to break and Torvald fails miserably in his role as savior and protector that Nora realizes all she has given up in the bargain. Once he turns on her, rather than protecting her, all deals are off. If he isn't willing or able to keep up his end of the bargain in the "Doll's House" they've created for themselves, she can no longer keep up her own role.
It's an interesting display of gender roles of a certain era, but the exaggerated characters can be somewhat grating. Or perhaps they aren't so exaggerated after all, and we've just come so far as a whole society that they just seem that way. At any rate, I do find the theme of being true to one's self an important one. Another prominent theme, the idea that the sins of the fathers are visited upon the sons, is woven beautifully throughout the play, and is one of my favorite aspects of the work.