"Was Marie Curie the only woman in science?" This question, asked by a college student trying to write an essay on women in science, planted a seed that grew over a decade of research into this informative and accessible biographical dictionary and bibliography. At the heart of this biographical dictionary are profiles of 186 women whose work is representative of the participation of women in the science of their time and culture. Despite the increasing attention devoted to women's history in recent years, our knowledge of many of these women is still meager, and the book will serve as much as a guide to future research as a resource for historians, librarians, students, and the general public. The book opens with a substantial essay relating the general state of science and philosophical ideas about the role of women in society to the actual participation of women in science over the past two and a half millennia. The classified, annotated bibliography that completes the book can be used as a general research tool as well as a source of information about the particular women whose lives are sketched in this work. The entries provide basic information on their subjects, are referenced to primary sources and other materials in the bibliography, and share an easily flowing narrative style. Beyond that, the length, approach, and focus of the entries have been allowed to vary within an appropriate range to suit the particular women whose lives they recount and whose achievements they evaluate.