Have you ever read an epistolary novel? First of all, what is an epistolary novel?
The term "epistolary novel" refers to novels that take the form of written documents, most likely letters. If you know the Bible, perhaps you're familiar with the Epistle of Paul to the Romans, or the Epistle of Paul to the Colossians, or to the Ephesians, and so on. "Epistle" is a synonym for letter.
This style of writing was much more popular prior to the 20th century, back when more people tended to write letters. Some novels are written entirely in an epistolary style (e.g., Dracula, The Moonstone, Pamela) while others use excerpts of letters or diaries (e.g., the works of Jane Austen, The Strange Case of Dr. Jekyll and Mr. Hyde). Epistolary texts can be used to advance the plot, such as when a letter that has traveled for weeks over land finally shows up at the last minute to change the outcome of events, or when a hidden diary is discovered that provides back story.
Why might someone choose to write entirely in an epistolary style? One reason is because it creates a sense of realism. Bram Stoker's novel Dracula is entirely epistolary, taking the form of diaries, letters, and newspaper articles, because Stoker wanted to create the sensation that this story had really happened and had been documented in various places by multiple persons. The author's original preface to the book (appearing in Powers of Darkness) is written as if he really discovered this material or acquired it from acquaintances whose identities he's decided to obscure. House of Leaves by Mark Z. Danielewski follows a similar path. This novel takes the form of a dossier, complete with a series of footnotes purportedly written by the person reading it that tell a parallel story. Such realism makes these books scarier.
The epistolary technique also gives readers a chance to get to know different characters more intimately. Elizabeth Hand's novel Wylding Hall is written as an oral history about mysterious events that occurred during the recording of an album in the 1970s. Each band member tells his or her account of what happened in his or her own words. Each piece of the puzzle is presented in a different voice and assembled to form a picture that the reader must interpret. Consequently, a novel told from the point of view of multiple narrators begs the question of which narrators are reliable. Does having many perspectives compensate for the narrator who may be lying, self-serving, or forgetful? Or does it complicate to deciding whom to trust?
Even when there is no question about the narrator's unreliability, an author may choose to prioritize that distorted worldview to enhance the horror of what is happening (e.g., various works by Poe, Guy de Maupassant's "The Horla," Robert W. Chambers's "The Repairer of Reputations.")
Sharing the experience of a minor character can be very entertaining when the character's voice is particularly vibrant. Lucilla Clack in Wilkie Collins's The Moonstone and Cousin Ernest Roger Halbard Melton in Bram Stoker's The Lady of the Shroud are officious bystanders in the main story, but when they cast their two cents in their own words, they are hilarious.
The epistolary style can also make the act of reading more fun and diverse. Instead of perusing one long narrative in the first person or third person, the reader gets to see different formats and different viewpoints, often presented through different fonts (e.g., transcripts versus diaries versus newspaper articles). House of Leaves effects this most dramatically by alternating the appearance of the material the readers experience.
The epistolary format has its drawbacks, too. Some readers dislike having to read atypical fonts or mentally shift gears among characters. Depending on how many characters are in play, it can be challenging to keep straight each person's voice.
Epistolary narratives can also reduce the sense of urgency and drama in the storytelling. Because these documents are produced after the fact, obviously the person who wrote them survived (at least long enough to make the record).
As a reader, I feel frustrated by horror stories that are written as a confessional narrative right up to the bloody end (e.g. various works by Lovecraft, Stephen King's "1922"). Who is going to sit still and write his memoirs while a monster is mere steps away?
I hear its loathsome claws on the floorboards in the hall! It's coming closer and closer. I know it's coming for me. I have mere seconds left. Agghh! Glug, glug, glug.
At least try to make it more realistic:
Something's at the door!
Damn, bullets don't work. Perhaps fire will.
No good. Tell my wife I love her. Agghh! Glug, glug, glug.
Although epistolary novels were more common in the 18th and 19th centuries, they seem to be experiencing a recent resurgence. Both World War Z and Devolution by Max Brooks are epistolary novels (the former an oral history, the latter a dossier of journals and interviews). The aforementioned Wylding Hall and Fantasticland by Mike Bockoven are both oral histories. Piranesi, the latest fantasy by Susanna Clark, is a collection of diaries.
Epistolary works have even expanded to include 21st century media. Things Have Gotten Worse Since We Last Spoke, a novella by Eric LaRocca, is written as a series of chat room logs and private messages. Joe Hill's short story "Twittering From the Circus of the Dead" is indeed a Twitter feed. Most recently, The Candy House by Jennifer Egan includes emails, diaries, and video game narratives.
My 2021 novel Smithy consists of diaries, letters, transcripts and news articles. I chose to utilize this narrative style primarily because I wanted to create a story that felt real (given that much of my story was inspired by actual events). I also wanted to feature different points of view to call into question which character(s) should be trusted and what each character might have to hide. Writing an epistolary novel was often tedious. I played journalist and wrote full-length newsmagazine articles from which I only used excerpts. I kept a calendar with me at all times to keep track of when letters might be exchanged and how often diaries should be written (and when I cut or rearranged scenes, I had to go back and change the timing of all the surrounding entries). My editor tried to discourage me from issuing Smithy as a full epistolary novel. He encouraged me to re-write it as a traditional narrative that occasionally used epistolary sequences. I declined to do that. Not only did I not want to have to re-do three years' worth of work, but I had chosen the epistolary format for good reasons. Perhaps he was right; some reviews have claimed the characters and events feel distant, filtered through writings instead of experienced in the moment. At the end of the day, I'm satisfied with what I produced, and when I find a review that remarks on how realistic the story seems, I feel victorious.
While it may not be an author's principal choice for what to write, the epistolary novel isn't going anywhere soon. An author might decide to write an epistolary novel for myriad reasons, but why might somebody choose to read one? Because it's a challenging, entertaining, unique, and rewarding experience. Now that you have a list of recommendations, try reading one for yourself and see what you think.