Stoker's choice of the epistolary form, a literary genre diminishing towards the end of the nineteenth century, also conveys his aim to establish a sense of realism in his story. The book is composed of extracts from characters" diaries, letters and telegrams, all having been carefully dated. The use of dates creates a context for the novel. Being set in a particular time frame, the narrative becomes more closely linked to the reader. As the story is told from several perspectives, the narrative cannot follow a single chronological line; Stoker must sometimes relate several events which happen simultaneously. It is for this reason that "Dracula" involves the use of flashbacks and jumps in time, which not only gives a realistic rendering of time, but also implies the use of a calendar during the elaboration of the novel.
Stoker regularly presents us with information that plays no decisive role in the plot. For example, we learn that Jonathan Harker's journal is "kept in shorthand" , while Dr Seward's is "kept in phonograph."(p.78), that Van Helsing's note is "not delivered" (p.243) and that two letters from Mina to Lucy remain unopened. This is exclusively intended to make the documents appear more authentic, by forming an accumulation of apparently insignificant details that actually function as factors of realism.
Another significant function of the epistolary form in "Dracula" is to create suspense. The unravelling of the plot is achieved mostly from the subjective points of view of three characters that do not have a global understanding of the situation- Jonathan Harker, John Seward and Mina Murray, and this in itself creates an immediate atmosphere of suspense and mystery. It is for this reason that Professor Van Helsing, the only character able to give a correct interpretation of events, is rarely given the opportunity to speak directly. His words are reported through the diaries of other characters, so that we are never given his intimate conviction about what is really taking place, until he informs the main protagonists.