* "The Adventures of Huckleberry Finn": John Grogan describes Marley as "a creature of habit," comparing his predictable behavior to that of Huckleberry Finn, who famously adhered to a strict routine. This comparison is particularly ironic given Marley's mischievous nature and the chaotic experiences he brings to the Grogan family.
* "The Lion, the Witch, and the Wardrobe": In one scene, John mentions that his wife, Jenny, is "always telling" him to think of Marley as "Aslan," the powerful lion from C.S. Lewis's classic children's novel. This allusion highlights the profound connection between Jenny and Marley, whom she views as a majestic and protective figure.
* "The Bible": John references a passage from the Bible when he says that Marley "was a beast of burden" who "carried the weight of the world on his shoulders." This alludes to the story of Jesus Christ, suggesting that Marley, despite his flaws, has a profound impact on the family.
* "The Odyssey": The book mentions Marley's ability to "find his way back home," even after wandering off for days, drawing a comparison to Odysseus's long journey home after the Trojan War. This reference underlines Marley's unwavering loyalty and his deep connection to his family.
These subtle allusions are woven into the narrative and contribute to the overall meaning of the story. They add depth and complexity, allowing readers to interpret the story on multiple levels. While not overt, they enhance the reading experience and leave a lasting impression.