In books, we often trust the narrator of the story and accept the secrets they reveal. But not all narrators are trustworthy. Have you ever considered using an unreliable narrator to spin lies for the readers of your books?
Liar, Liar, Pants on Fire
Some narrators are unreliable. It's a rarely-used but quite effective literary technique. When it's done well, it will lead to a shocking twist ending that takes readers by surprise. One of the best examples of this technique is The Murder of Roger Ackroyd, by Agatha Christie.
The big twist ending was a shock for audiences of the day because it was so new. Literary critics have called it a masterpiece, and one of the most influential crime novels ever created. The narrator in this book is Dr. James Sheppard, the victim Mrs. Ferrars. Roger Ackroyd says she committed suicide...but then he, too, is found dead. In the epilogue of the book, the lying narrator admits to some of the literary techniques used to lead the reader astray.
It's truly an epic novel and the perfect example of this technique. The unreliable narrator can be used in any genre, by the way. This is not a character who must live inside crime. The narrator can be an active part of the story itself, as is Dr. Sheppard in The Murder of Roger Ackroyd, or they can be someone who is only telling the story second- or third-hand.
It should always be a twist when the audience learns that the narrator has been lying the whole time. Because narrators are inherently trusted by readers, half the work of giving the readers a twist is already done.