Seuss is famous for creating a style and tone that was one-of-a-kind. In The 500 Hats of Bartholomew Cubbins, though, he's definitely borrowing from the fairy tale tradition. But don't go discrediting the book just because it's not rocking the signature style we associate with the Seuss name. Borrowing can make a book just as awesomely original; so long as it's done right.
And The 500 Hats does it right.
Seuss borrows his tone from such classic children's stories like Grimm's Fairy Tales. Take this example from the opening of the Brothers Grimm's "The White Snake":
A long time ago there lived a King who was famed for his wisdom through all the land. Nothing was hidden from him, and it seemed as if news of the most secret things was brought to him through the air. But he had a strange custom; every day after dinner, when the table was cleared, and no one else was present, a trusty servant had to bring him one more dish. (Source)
Now, here's the opening from The 500 Hats:
In the beginning, Bartholomew Cubbins didn't have five hundred hats. He had only one hat. It was an old one that had belonged to his father and his father's father before him. It was probably the oldest and plainest hat in the whole Kingdom of Didd, where Bartholomew Cubbins lived. (1)
You can see the shared tone in phrases like "A long time ago" versus "In the beginning" and "famed through all the land" versus "the oldest and plainest hat in the whole Kingdom of Didd."
Now, if you swing over to our "Meaning" section, you'll see that The 500 Hats centers on the foolishness of rules and those who will go to great lengths to keep them. In contrast, Grimms' fairy tales are often about enforcing rules and the proper order of things.
So while the tones match up quiet nicely—minus Seuss's quirky sense of humor, of course—the purpose of The 500 Hats is the exact opposite of many of Grimm's Fairy Tales. By taking the tone but ditching the moral, Seuss adds a level of irony that makes the story funnier for children and enjoyable for adults, too. Ta-da!