Season 6, Episode 8: "Recon"
Season 1, Episode 19: "Deus Ex Machina"
Season 1, Episode 18: "Numbers"
A combination of science fiction, romance and adventure, A Wrinkle in Time by Madeleine L'Engle is the story of a teenage time traveler who takes her brother and a friend with her to rescue her father, a scientist being held prisoner by an evil force. Lost and A Wrinkle in Time share overt themes about religion and faith, time and space travel with multiple dimensions and an evil force called The Black Smoke and The Black Thing respectively.
In Season 1, Episode 18, "Numbers," we find Sawyer reading A Wrinkle in Time on the beach. In the very next episode, Season 1, Episode 19: "Deus Ex Machina," he's on the beach reading the book when Jack offers to help him find some glasses for his "hyperopia" (farsightedness). Fast forward to Season 6, Episode 8, "Recon," Charlotte finds A Wrinkle in Time on Sawyer's dresser in his sideways reality.
If we aren't reading too much into it, consider this: In the book, Charles Wallace has psychic qualities. In the Lighthouse episode, number 108 on the lighthouse wheel is Wallace—one that Jacob hints is coming to the island. 108 is the sum of all the numbers and has great significance in Lost lore.
Read an excerpt from Madeleine L'Engle's book Camilla