There two main themes of "Daisy Miller" by Henry James are that of the role of women and of the relationship between Europe and America.
the first idea found is the notion of American "innocence" versus European sophistication. The Europeans and long term expatriates of the novel have a very sophisticated code of manners, emphasizing restraint and propriety. The Americans are seen as naive, open and spontaneous. This raises a question of which is morally better.
The role of women is addressed in Daisy's unconventional behaviour such as walking unchaperoned and flirting. The main question of sexual morality is whether Daisy's apparent impropriety, because it is innocent, is actually in truth sinful or immoral compared to the surface restraint of the Europeans or actually more pure because it is not so self-aware.