Clifford DeVoe was a failed lawyer who bitterly ended his career in 1933. Realizing that many of the criminals he had encountered had the skills but not the brains to rule Gotham City's underworld, he started a new career as the brain behind small-time villains. As the Thinker, he was defeated by the original Flash/Jay Garrick, his most recurrent foe. He always sought out new scientific devices to use and his most important was the "Thinking Cap", a metal hat that could project mental force. The Thinker would use this device repeatedly over the years.