What do you call a sleeping book?

This clever little joke plays on our understanding of common phrases and literal interpretations. The humor mechanism here is classic wordplay, specifically a pun that hinges on the double meaning and association of "bedtime" and "story." The setup creates a slightly silly, anthropomorphic image of a book actually catching some Zs, inviting us to think about what a "sleeping book" would be called in a literal sense.

The punchline then brilliantly pivots to "a bedtime story," which isn't a book that's asleep, but rather a narrative told before sleep. This phrase immediately evokes images of cozy evenings and comforting tales, a time when both books and people might be settling down for the night. Bedtime stories themselves have a long and cherished history, serving as a gentle ritual for generations, preparing minds for slumber with imaginative tales. The joke cleverly connects the literal act of sleeping with the traditional context of stories told at bedtime, creating a satisfying and amusing semantic twist.