Einstein's work on the general theory of relativity, which he developed between 1907 and 1915, is another significant focus of Isaacson's biography. The author provides a clear and concise explanation of the complex mathematical concepts underlying this theory, which revolutionized our understanding of gravity and space-time. As Einstein's fame grew, so did his public profile, and Isaacson explores the tensions between Einstein's desire for solitude and his increasing celebrity status.