James Dean, 24 Years Old
James Dean quickly overtook Hollywood in the 1950s, becoming one of the most coveted actors in the industry. His most acclaimed role was in "Rebel Without a Cause" in 1955. He defined the "loner" character both on and offscreen. He died suddenly in a car accident when he was just 24 years old and was given two posthumous awards, including an Academy Award nomination for Best Actor.