By the time you read these opening lines you have already formed an impression of this book and perhaps established certain fundamental truths about it. These will most likely be challenged or confirmed as you read, but the point remains that you have established them using some textual and some non-textual signifiers. You encounter thresholds with each book you come across: the cover, the picture: what is inscribed on the outside of the volume either in text or in image. These signifiers lead you to conclusions about genre, audience, relevance and scope, and those conclusions are altered, or confirmed or dismissed, upon delving further into the object. In other words, you have first encountered the material form of the book: you have first read that materiality, and you read that materiality every time you come into contact with a physical text. This text has a physical reality. The physical, material nature of the text can change (you may be reading this, for instance, on a computer screen), but the materiality of the text always contributes to its meaning.