This book is the first comprehensive study of legal, historical and economic aspects of marriage as practised during the Middle Ages, in Egypt and Palestine, by members of the distinct Jewish movement known as Karaism. This study is based on original mediaeval manuscripts written in Hebrew, and recovered from the famous Cairo Geniza. Sixty-five manuscripts, most of them previously unpublished, are edited and translated in the second part of the book. The detailed and accessible analysis of their contents, language, formulation and palaeography sheds a new light on Karaite legal and linguistic tradition, and provides a unique source for our understanding of early Karaism, and of mediaeval Jewish history in general.