The Scarlet Letter is the masterpiece of Nathaniel Hawthorne, which was written between 1848 and 1851. It is a first great American novel. The story is set on the adulterous love between a puritan minister, Arthur Dimmesdale, and a married woman, Hester Prynne. Adultery is not the main focus of the Scarlet Letter, and the novel is not really a love story. The main interest of the novel is not the love between Hester Prynne and Arthur Dimmesdale. Its focus is on the attitude of the people around them towards their adultery and their moral situation in which they have to suffer in the long years. Indeed, when the novel unfolds, it is the emotional, moral and psychological effects and consequences of the sin of adultery and the respective struggles between Hester Prynne and Arthur Dimmesdale that arouses our interest.  Hawthorn is more interested in the effect of the hidden, tormented and festering sense of guilt which is gradually consuming Dimmesdale, and in a last analysis, he becomes the center of the book.
It seems that the novel is the history of a triangle set down in a New England town where people piously believe in Puritanism. But after taking a closer reading of the book, we finally realize that this is not essentially a triangle after the event. The adulterous sin has already been committed. Hawthorn is concerned only with the effects of that sin, whose mark has grown more and more terrible and obvious as time passes on Hester Prynne and Arthur Dimmesdale. His problem, then, is what effect will the consciousness of sin have on these people when one of them is a sensitive and neurotic creature who has concealed his participation in the sin, while another has suffered from the public obloquy of revelation, and a third is an old man eaten up with the jealous madness of revenge. (Bradley 250). The Puritan consciousness of sin, which has evinced in some Hawthorn’s short tales, is the dark thread that gets the plots of the novel connected and makes the readers follow through the ghostly labyrinth of the Scarlet Letter. None of his works are so intensely impregnated with the after-sense of the old Puritan consciousness of life to which allusion has so often been made.
The novel shows us the cruelty of the Puritanism and exposes the hypocrisy and the evil of the religion through the description of the three main characters, Hester Prynne, Arthur Dimmesdale and Roger Chillingworth. Hester Prynne, who is charming and beautiful, not caring much about the worldly possessions, married a freaky, aged and hypocritical scholar, Roger Chillingworth, who is so concentrated on the classical books. There is no real love between them. Hester Prynne is lonely and depressed with the marriage without love. Then the husband is enslaved and loses contact with Hester Prynne, who finally falls in love with a handsome minister, Arthur Dimmesdale. Hester Prynne gives birth to a girl named Pearl.
Because of the adulterous relationship, Hester Prynne gets punished wearing a Scarlet Letter A on her bosom as a warning. Roger Chillingworth returns and decides to take a revenge on Arthur Dimmesdale after finding out that the minister is the adulterous partner of his wife. Arthur Dimmesdale died after admitting this guilty, and people also forgive Hester Prynne for her kindness and generous behavior.
Many of us are very familiar with this kind of artistic application, symbolism, which is often used by many writers. But it is possible that some can not clearly say what symbol really means. First, we should have a good understanding of the explanation of the symbol.
The word symbol derives from a Greek word which has the meaning of to throw together (Chadwick 20). Symbol means an act, a person, a thing, or a spectacle that stands for something else, usually less palpable than the named symbol. The relationship between the symbol and its referent is not often one of simple equivalence. It is an object, animate or in animates which stands for something else. For example, a dove symbolizes peace; scales, justice; the rose, love. Gestures and actions can also be symbolic. Nodding head means agreement, shaking head stands for disagreement. 英文论文《红字》的象征意义(2):http://www.751com.cn/yingyu/lunwen_18617.html