Look, if you don't have Elephant & Piggie on your shelf, you're missing out on the gold standard of early childhood literacy. Mo Willems managed to take the 'learning to read' format—which is usually as dry as unbuttered toast—and turned it into high-energy improv comedy for toddlers.

The Thank You Book is the series' victory lap. It’s sweet, it’s funny, and it teaches gratitude without being a preachy 'moral of the story' slog. It’s one of the few books you won’t mind reading for the tenth time in a row because the comedic timing is actually baked into the page turns.