A ladder accessory configured for releasable attachment to a side of a ladder rail includes a shoe assembly having at least one of a first shoe and a second shoe, an adapter releasably attached to one of the first and second shoe, the assembly constructed and arranged for increasing traction between a standard ladder foot and a ground surface by engaging the foot without the use of tools. The system generally employs radio frequency identification technology to electronically detect positions of books of the physical bookshelf, as well as last viewed pages of each individual book. The air evacuation passage is used to selectively apply and then maintain a vacuum to the vacuum chamber and cavity.