This book examines the role of linen undergarments in concepts of propriety and health in early-modern England. While medical history has written about hygiene, dress historians about linen undergarments, and women's history about laundry, this is the first book to bring these separate narratives together. Acknowledging the difficulties in researching the habits of cleanliness in the past, particularly the unreliability of personal testimony for reasons of bias and modesty, the study sets out a methodology for researching aspects of bodily hygiene, first delineating in full what the advice was in both conduct and medical literature. In the latter, clean "wearing" linen was believed to play an important role in good health, and dirty linen implicated in the spread of disease - particularly plague and "fevers." However, the relationship between medical theory and the practice of "clean linen" proved to be a complicated one. Research has uncovered specific hypotheses during the late seventeenth and early eighteenth centuries that proposed that flannel was a better material for undergarments, and that providing clean linens for a fever patient might prove fatal. Dress and Hygiene in Early Modern England analyses these conflicting concepts during the long-seventeenth century, and their resolution in favour of "clean linen" in the late eighteenth century. By incorporating not only dress, social and medical histories, but also evidence from surviving clothing, the book serves as an example of an interdisciplinary methodology and a potential model for other histories of other "unspoken" subjects.