This book studies the early modern phenomenon of the increasing production and consumption of blue-hued paper, a material used widely in Italy as a drawing, writing and printing support as well as an ephemeral wrapping. Until recently researchers overlooked blue paper as an object of curiosity and worthy of study, often judging that, because of its assumed less refined fabrication and mottled colour compared to the finest contemporary white papers, it was a poor-quality product of lowly function and no particular interest. Close looking, a method of visual examination used regularly by a wide range of professional disciplines, is used here to examine a selection of surviving paper artefacts from the period c.1400-c.1600. Combined with a reconsideration of the extant documentary sources and placed in a broad historically-based synchronic context, this book presents new information and interpretations to enrich the nascent blue paper corpus.