Maria tries to reach a book on the top shelf, because clearly, it was put in the wrong place; and as the librarian of the Hush Valley Public Library, such a glaringly visible oversight will not remain uncorrected. Though standing at only 3'9", just trying to reach her quarry is a tricky feat to accomplish on its own; even with a stepping stool present to help boost her height.
Oh and don't worry, despite it's simple appearance, that stepping stool is actually capable of holding someone five times Maria's weight (what with it being reinforced with a durable titanium-alloy core and all that). =p
And on an artistic note, drawing that shelf (and subsequently, all of those books) took way longer than it really should have. ^_^;