the opening chapter of the novel, Stevenson takes care to ensure that Mr. Utterson comes across as a very trustworthy, rational, and sensible narrator. He is described as a "lawyer," and "embarrassed in discourse." The respectable job implies that he is trustworthy, and "embarrassed in discourse" implies that he is not one for gossiping. The reader is thus more inclined to believe that the events he describes are accurate and unadorned. In chapter 9, the narrator is Dr. Lanyon, who is likewise established as a trustworthy character and a good friend of Utterson's. We are therefore inclined to believe that his description of the transformation is reliable. Chapter 10, as noted above, takes the form of a letter written by the since deceased Dr. Jekyll. Dr. Jekyll may not have been trustworthy when he was alive, but he had no reason to lie in a letter only intended to be read after his death. We are therefore inclined to trust that his description of events is also reliable.

All three narratives also fill in gaps left by one or both of the other two narratives, and thus all three narratives fit together like the pieces of a jigsaw. We are inclined to believe that the supernatural explanations have a place in an otherwise realistic account not only because we trust all three narrators, but because all three narratives seem to fit together so perfectly.

Broadly speaking, Stevenson does this in two ways. First, the narrative is marked by a strong narrative voice. There is no pretense of objectivity here. This is a story that is being told by a sharply defined voice, like you're listening to it around a fire. Look at how many interpretations are made in this single line: " MR. UTTERSON, THE LAWYER, was a man of a rugged countenance, that was never lighted by a smile; cold, scanty and embarrassed in discourse; backward in sentiment; lean, long, dusty, dreary, and yet somehow lovable."

 The second technique is by the level of detail given to the weird (supernatural, etc.) and the amount of emotion layered on the realistic. These qualities cause the two categories to blend.

You might consider how characterization, setting, and diction are used to create mystery and tension in The Strange Case of Dr. Jekyll and Mr. Hyde.

The opening of the novel begins with a description of Mr. Utterson, whose goal is to discover the mystery of Dr. Jekyll and Mr. Hyde. His name in itself connotes secrecy, and the description of his demeanor is somber. His face is "never lighted by a smile," has a "rugged countenance," and is "scanty and embarrassed in discourse." Mr. Hyde is described as "pale and dwarfish," and he possesses a personality that has a "murderous mixture of timidity and boldness." He speaks with a whisper in a voice that is "broken." Descriptions such as these heighten the tension of the characters and their interactions with each other.

You might also consider how the tension is increased through the setting. The conflict occurs in Victorian England, amid references to servants and strict class distinctions. Themes of repression—and of the anger resulting from such limitations—provide motives for Dr. Jekyll's actions. You might also notice how often fire is used in descriptions of setting, symbolizing both enlightenment and fostering greater tension.

The specific words Stevenson chooses, or the diction of this work, also contributes to the overall mystery and tension. Just as Dr. Jekyll and Mr. Hyde are juxtaposed in their characterizations of goodness and evil, other images and ideas are juxtaposed to further demonstrate the mystery of human nature.

Dr. Jekyll is described as having "pale ... lips" with eyes that grow in "blackness" when challenged. In the end, Hyde reflects that "all human beings ... are commingled out of good and evil." You might also consider the way words are chosen to convey a negative tone. In the chapter "The Last Night," the setting is described as "wild" and "cold." The moon itself looks as though "the wind had tilted her." The wind is so forceful that it "fleck[s] the blood into the face." The streets are "bare" and "London [has never looked] so deserted." Mr. Utterson "struggle[s]" with a "crushing anticipation of calamity." This quick succession of words connoting adversity and unfavorable conditions creates greater mystery and tension, as well, a consistent set of stylistic choices that recur throughout the story.

I think that Stevenson's style is one distinct way he is able to communicate menace and suspense in the narrative. Nabokov noted this in his analysis:  "Stevenson had to rely on style very much in order to perform the trick, in order to master the two main difficulties confronting him: (1) to make the magic potion a plausible drug based on a chemist's ingredients and (2) to make Jekyll's evil side before and after the"hybridization" a believable evil." Nabokov's point helps to explain how menace and suspense are enhanced in the narrative.  Stevenson constructs a narrative where one recognizes the validity of both expressions of reality.  Stevenson's style is one where he continually alludes to the duality that exists within the human predicament:  "I never saw a man I so disliked, and yet I scarce know why ... He gives a strong feeling of deformity, although I couldn't specify the point ... I can't describe him." By constructing a reality where a sense of that which is socially accepted is offset by a "haunting sense of unexpressed deformity," Stevenson is able to construct menace and suspense.   The stark reality of both visions of reality is where Stevenson is able to communicate a sense of menace and suspense.

Along these lines, menace and suspense is evident in trying to figure out which force will win.  The socially acceptable force of Henry Jekyll is challenged with the “murderous mixture of timidity and boldness" in Hyde.  Both forces are shown to be equally dominant.  As much as one wants to embrace Jekyll because he reaffirms social structures, one is repulsed by Hyde.   Menace and suspense are displayed in the ongoing challenges within both personalities.  At some point, the reader understands that only one will win.  Which one becomes the source of menace and suspense.  If Hyde wins, to a great extent, redemption is denied.  When Jekyll realizes the need to commit suicide, the reader's fear and their own perceptions of internal suspense and menace subside.  Exploring the presence of both dynamics, what Jekyll would call "the agonized womb of consciousness," is where menace and suspense reside. In a world where singularity is sought and in a reader that embraces singularity from duality, Stevenson enhances menace and suspense because one of these forces must win.  Menace and suspense exists in how such agony is resolved.