Marginalia in early modern and medieval texts - printed, handwritten, drawn, scratched, colored, and pasted in - offer a crazy quilt composed of fragments of how people, as individuals and in groups, interacted with books and manuscripts over often lengthy periods of time. The chapters in this volume build on earlier scholarship that established marginalia as intellectual method (Grafton and Jardine), as records of reading motivated by cultural, social, theological, and personal inclinations (Hackel and Orgel), and as practices inspired by material affordances particular to the book and the pen (Fleming and Sherman). They further the study of the practices of marginalia as a mode - a set of ways in which material opportunities and practices overlap with intellectual, social and personal motivations to make meaning in the world. They introduce us to a set of idiosyncratic examples - erotic images doodled in a medical manuscript, cut---and---pasted additions to printed volumes, a marriage depicted through shared book ownership, for example - and reveal to us in case studies the unique value of marginalia as evidence of phenomena as diverse as religious change, scientific discovery, and the history of the literary canon. They also raise broad historical, cultural, and theoretical questions about the relationship between animal parts and human society, the construction of authorship, the ways in which exchange of words and objects align, the strange, marvelous, metamorphic thing we call the book, and the equally multiplicitous, eccentric, and inscrutable known as the reader.