Gone Girl — Gillian Flynn (2012)

Gone Girl popularized the unreliable narrator technique, making it the defining feature of 21st-century commercial literary fiction and inspiring countless 'Gone Girl for X' pitches. Its sharp dissection of marriage and deception delivers a shockingly original mystery, ranking it as the most influential crime novel of the 2010s. It outperforms #4 The Name of the Rose in cultural impact, with 20 million copies sold in its first five years alone.