If you were fascinated by the intricate conspiracies and shadowy organizations in Leviathan, you'll be drawn into Foucault's Pendulum. Eco's novel follows three editors—Casaubon, Belbo, and Diotallevi—who invent their own grand theory of conspiracy, only to find themselves entangled in a very real and dangerous web of secret societies. The book is rich with historical allusions and intellectual puzzles, offering a similarly labyrinthine and mind-bending experience.

If you relished the biting wit and satirical edge woven throughout Leviathan, you'll love Catch-22. Heller's masterpiece skewers military bureaucracy with absurd humor and dizzying logic, following the misadventures of Yossarian and his fellow airmen. The novel's hilarious yet poignant commentary on the madness of systems and authority will appeal to readers who appreciate irreverent, clever storytelling.

If you were captivated by the dizzying complexity and interwoven plot threads of Leviathan, you’ll find The Illuminatus! Trilogy an electrifying ride. This book explodes with overlapping storylines, secret codes, anarchist plots, and sudden reversals—think Joe Malik, Simon Moon, and Hagbard Celine racing across continents in pursuit of hidden truths that forever change their worldviews.

If you enjoyed navigating the ethical gray areas and larger-than-life personalities in Leviathan, Pynchon's Gravity's Rainbow will stretch your imagination even further. Tyrone Slothrop and a wild cast of characters operate in a world riddled with paranoia, double-crosses, and questionable motives. The blurred lines between hero and villain create a rich, challenging reading experience.

If you were intrigued by the playful, non-chronological structure of Leviathan, you'll be mesmerized by House of Leaves. Danielewski's narrative weaves together footnotes, unreliable accounts, and stories within stories, building a tense, labyrinthine experience as Johnny Truant unravels the mystery of the Navidson Record—where the book’s structure itself becomes a puzzle to solve.