This book is the most mature and comprehensive statement of Mary Astell's religious and philosophical views. It also represents the culmination of Astell's feminist project to teach her fellow women how to lead useful lives of virtue and wisdom. The main purpose of this work is to instruct women about the ultimate nature of reality, the true source of happiness, their duties and obligations to God, and about "how best to live" and how to treat other people. This volume offers the first complete modern version of the 1717 second edition. It provides a fully modernized text, a scholarly introduction, biographical and bibliographical information, general historical-intellectual background, and definitions of obscure and archaic terms.