This book presents the author's confrontation with Jean-Jacques Rousseau's Les rêveries du Promeneur Solitaire, the philosopher's most beautiful and daring work, as well as his last and least understood. Bringing to bear more than thirty years of study of Rousseau, the book unfolds an original interpretation in two parts. The first part approaches the Rêveries not as another autobiographical text in the tradition of the Confessions and the Dialogues, but as a reflection on the philosophic life and the distinctive happiness it provides. The second turns to a detailed analysis of a work referred to in the Rêveries, the “Profession of Faith of the Savoyard Vicar,” which triggered Rousseau's political persecution when it was originally published as part of Émile. The examination of this most controversial of Rousseau's writings, which aims to lay the foundations for a successful non-philosophic life, brings to light the differences between Natural Religion as expressed by the Vicar and Rousseau's Natural Theology. Together, the two reciprocally illuminating parts of this study provide an indispensable guide to Rousseau and to the understanding of the nature of the philosophic life.