If books are brilliant because they are full of wonder, consider how wonderful the bookshelf is. More than a tool—akin to how the book is more than a technology—the bookshelf organises reading, knowledge, and knowledge-making. It’s physically solid and has a comforting fixity. It’s movable, expandable, and contractable. It can be multiplied, encased, left to float on walls, become a room, be the base building block of a building. And still, a single shelf can be a library in its own right; and any horizontal surface can be a shelf, provided that it holds books.