Shedding new light on Einstein's study of unified field theory, this book will interest physicists, historians and philosophers of science.Shedding new light on Einstein's later work, this book explores Einstein's belief that he could find a unified theory of all of nature's forces by repeating the methods he used when formulating general relativity. This book will interest physicists, historians and philosophers of science.Shedding new light on Einstein's later work, this book explores Einstein's belief that he could find a unified theory of all of nature's forces by repeating the methods he used when formulating general relativity. This book will interest physicists, historians and philosophers of science.Why did Einstein tirelessly study unified field theory for more than 30 years? In this book, the author argues that Einstein believed he could find a unified theory of all of nature's forces by repeating the methods he thought he had used when he formulated general relativity. The book discusses Einstein's route to the general theory of relativity, focusing on the philosophical lessons that he learnt. It then addresses his quest for a unified theory for electromagnetism and gravity, discussing in detail his efforts with Kaluza-Klein and, surprisingly, the theory of spinors. From these perspectives, Einstein's critical stance towards the quantum theory comes to stand in a new light. This book will be of interest to physicists, historians and philosophers of science.Introduction; 1. Formulating the gravitational field equations; 2. On the method of theoretical physics; 3. Unification and field theory; 4. Experiment and experience; 5. The method as directive: semivectors; 6. Unification in five dimensions; 7. The method and the quantum; Conclusion; Bibliography; Index. & the reader who perseveres will be well rewarded with an excellent understanding of Einstein's journey and a sophisticated appreciation for the challenge of unification. This is an excellent historicl“.