A mysterious book

Note: I'm back! Sorry for the long pause. There are so many workloads that I complete NNN by accident.

The next day, Henry went back to his old school. He quickly found Mary Margaret Blanchard in his old classroom.

When Mary heard about his purpose, she said: "There are many books here. Which one do you need?"

"I don't know, but it should be a book only you can give to me."

She thought for a moment, then stood up and took out a book from her shelves, handed it to Henry:

"I found this book in my closet last night. Is this the right thing?

Henry opened it and found that it's a storybook.

"This is just a fairy tale book. I haven't read it carefully, but at the first look it's no different from normal storybooks you can find anywhere."

This was not Henry's case: for him, a storybook was NOT something he "can find anywhere". He thanked Mary, put the book into his bag, and returned home.