This richly annotated facsimile edition of "The Foundation of General Relativity" introduces a new generation of readers to Albert Einstein’s theory of gravitation. Written in 1915, this remarkable document is a watershed in the history of physics and an enduring testament to the elegance and precision of Einstein’s thought. Presented here is a beautiful facsimile of Einstein’s original handwritten manuscript, along with its English translation and insightful page-by-page commentary that places the text in historical and scientific context. Hanoch Gutfreund and Jürgen Renn’s concise introduction traces Einstein’s intellectual odyssey from special to general relativity, and their essay "The Charm of a Manuscript" provides a delightful meditation on the varied afterlife of Einstein’s text. Published on the centennial of Einstein’s general theory of relativity and featuring a foreword by John Stachel, this handsome edition also includes a biographical glossary of the figures discussed in the book, a comprehensive bibliography, suggestions for further reading, and numerous photos and illustrations throughout.