William Burnside, PhD, also known as the Captain America of the 1950s, is a fictional character appearing in American comic books published by Marvel Comics. He was created by writer Steve Englehart and artist Sal Buscema in Captain America #153–156 (Sept.–Dec. 1972) as an explanation for the reappearance of Captain America and Bucky in 1953 in Young Men comics and their subsequent adventures in the 1950s. It established through retroactive continuity that the character was a completely different one from the original Captain America, who was firmly established in The Avengers #4 as disappearing near the end of World War II. Since this revelation, the character serves as a foil personality to his predecessor.