I’m a bit intrigued in their comment that the book would play a part in the rest of season 3. There are oodles of ways that could play out, but here’s a theory.
In newly cursed Storybrooke, Miss Peridot (WWW) is in a position of power and trust. She’s lovely and everyone likes her. Possibly she’s the new Mayor or teacher.
As the town is in an uproar wondering who cursed them, Henry is sitting at an outside picnic table reading The Book while pretending too do his homework. Miss Peridot walks by and they exchange a casual greeting. “Hi, Miss Peridot.” “Good afternoon, Henry. It’s nice to see you so attentive to your schoolwork.”
As Miss Peridot continues by, Henry glances at his book, then quickly glances up. “Miss Peridot!” “Yes Henry?” He sees Miss Peridot transformed to the Wicked Witch. “Never mind.”