"The Custom House" is a long prologue to The Scarlet Letter, and when one has a good grasp on both, it seems impossible to read one without the shadow of the other.

In "The Custom House," Hawthorne offers a defense for his telling the story and tries to legitimize the story through the fiction of finding the artifact of the letter and the old Custom House officer's description of the early days in the colony and of Hester's story particularly.

In this prologue, Hawthorne also broods on his own family history, with attention to his ancestors's participation in the Salem Witch Trials and their religious oppression of Quakers. This intolerant mindset, for which Hawthorne feels an inherited shame, becomes the subject of the novel's critique as well. These characters in the novel are the same ones who participated in the Pequot War and whose children would prosecute villagers as witches. The novel seems to exist in between those time periods, and we can see on a small scale in Hester's story the psychological damage done when intolerance and an absolute commitment to theocracy prevails. At the same time, he distances himself somewhat from the far more exuberant Transcendental philosophy of Emerson, with whom he was friendly. Unlike Emerson, Hawthorne was less optimistic about humanity's ability to find a proper course simply by living according to Nature's precepts. The novel seems to argue for a mode of life somewhere in between Puritanism and Transcendentalism.

Lastly, "The Custom House" contains an ars poetica, or an instruction on how to read the novel. Hawthorne speaks of the transformation objects take when seen through moonlight. Everyday objects, when seen through the filtered moonlight, participate in both realism and romanticism. This suggests a connection to the Dark Romantics, such as Poe and Hawthorne. This is the narrative point of view in the novel, looking at the events concerning Hester, Arthur, and Pearl through this slightly distorting or imaginative light.

One little trick Hawthorne plays in "The Custom House" is to make the prologue so tedious and to even announce at times that it is tedious. The first brief chapter is highly allegorical. Then, the rest of the novel is a mixture of realistic portraiture and supercharged symbolism, and this is the style of writing Hawthorne hoped to inaugurate under the label "Romance."

There are some similarities. First and most important is the presence of the narrator. It is his voice rather than his identity that is significant. He is established in the introduction as a man of imagination and curiosity, and these traits are reflected in the way he tells the the story. As he relates it, his information having been gleaned from old documents and old tales, his voice is often ambiguous and filled with qualifications as he offers up one possible version of events versus another. He asks many questions. His curiosity inspires curiosity in the reader. The truth of the events he relates is as much a mystery to him as to the reader.

There are also some similarities between the narrator and, strangely enough, Hester Prynne. Both live in circumstances where they really do not belong. The narrator is at heart a writer, trapped in the mundane life of the Custom House and surrounded by people far different from himself in their values, behavior, and temperament. He goes about his business, performing his duties, but he does so without really belonging. He is an outsider who observes those around him while remaining essentially detached. It is understandable why he would be drawn to Hester, intrigued by a woman who lived and died in her own difficult circumstances among people so unlike herself. Like Hester, the narrator is emotional, passionate, and nonjudgmental, very much aware of the unresolved mysteries in life.