Book 91 (The String Book) by Keith A Smith is study of light, shadows, moment & sound. Every page of this wordless book contains a different geometric shape or design, which comes out of the way the strings & the hand-punched holes are placed. But, this book isn't just about each page; it's about the task of turning the pages. With every turn, you hear the rubbing of the linen thread against the pages & some are louder than others, visually & aurally. Shadows create new shapes with the turns as light glides through the holes and slices through the strings. A triangle can appear out of a single string.
Book 91 challenges the idea of a book. Although the mainstream thinking of a book means to contain words or a narrative, I believe a book only needs a beginning & an end. In Book 91, it feels like there is a string being pulled from the beginning to end, encountering other strings & collaborating with them. You can feel the tension of the stings, almost like building tension during in a plot.
For further reading & pictures, here's a link to Judith Klau's analysis of Book 91 at the JCBA website.