A basic maneuver necessary to reading a codex is the turning of its pages, which demands the reader to touch the book directly and repeatedly. As they do so they progressively consume the book’s meaning and advance through its body in time. Turning is also performed when operating tools stored inside books to obtain information, like the volvelles found inside Hevelius’s Selenographia and other books of astronomy. The maneuver fundamentally entails change and metamorphosis, whether on a narrative level, as with children’s movable books, or an organic one, as with an artist’s book made up of processed cheese slices. The greatest turn is a cognitive one, when the reader’s mind is transformed as much from touching and turning the pages of a book as from reading the text printed on them.