Who is Harry gold in the book bomb?

In the book "Bomb" by Steve Sheinkin, Harry Gold is a pivotal figure who becomes a key informant in the atomic espionage case during World War II. He was a member of the Communist Party and played a crucial role in passing secret information about the Manhattan Project to the Soviet Union. Gold’s actions significantly impacted the Cold War and the development of nuclear weapons. His story illustrates the complexities of loyalty and betrayal during a time of intense global conflict.