I have recently started reading through the Harry Potter series yet again and noticed something quite peculiar in Harry Potter and the Prisoner of Azkaban; while shopping at a wizarding book store (sorry, can't remember the name), the store owner cries out in frustration, obviously irritated by the newest book, The Monster Book of Monsters, yelling. "I'm never stocking these again, never! This is worse than when we ordered over 200 copies of the Invisible Book of Invisibility; never could find them." Couldn't the shopkeeper have used the Accio spell to summon the books, or was it implied at some point in the Harry Potter universe that this book owner is actually a Squib, and therefore cannot perform magic? I have not yet found any answer on this, and any help would be appreciated.

I have recently started reading through the Harry Potter series yet again and noticed something quite peculiar in Harry Potter and the Prisoner of Azkaban; while shopping at a wizarding book store (sorry, can't remember the name), the store owner cries out in frustration, obviously irritated by the newest book, The Monster Book of Monsters, yelling.

"I'm never stocking these again, never! This is worse than when we ordered over 200 copies of the Invisible Book of Invisibility; never could find them."

Couldn't the shopkeeper have used the Accio spell to summon the books, or was it implied at some point in the Harry Potter universe that this book owner is actually a Squib, and therefore cannot perform magic? I have not yet found any answer on this, and any help would be appreciated.