Walter Isaacson
Einstein's major breakthroughs were driven not merely by mathematical ability, but by a rebellious non-conformity, visual thought experiments, and a refusal to accept established scientific authority.
Einstein's unusual independence let him question foundational assumptions of classical physics that others accepted.
Instead of starting with complex mathematics, Einstein relied on highly visual thought experiments, such as imagining himself riding alongside a light beam, to unravel the mysteries of the universe.
His special theory of relativity shattered the concept of absolute time and space by treating the speed of light as constant and simultaneity as relative to the observer.