This volume makes available for the first time critical editions of John Locke's A Vindication and A Second Vindication of the Reasonableness of Christianity, in which Locke defends his interpretation of the New Testament and of the Christian Religion against charges of heterodoxy. These works contribute greatly to our understanding of Locke's Christian commitments, which it is now recognized played an important role in shaping his philosophical opinions; they also demonstrate his sophistication as a biblical scholar, and the breadth of his theological learning. The texts are accompanied by a historical introduction explaining the origin of the works and setting them in context. In addition to a textual introduction and critical apparatus, editorial notes help to clarify the text. The volume also includes a French translation and abridgment by Pierre Coste, a Huguenot scholar, who was patronized by Locke and worked on his translations while residing in Locke's household. This definitive edition is an important contribution to an understanding of the development of modern enlightened Christian attitudes.