The research of prominent scientist Albert Einstein was profoundly influenced by the Einstein-Szilard letter in 1939, which alerted President Franklin D. Roosevelt about the potential of nuclear weapons. This significant historical event not only marked the beginning of the Manhattan Project but also prompted Einstein to reflect on the ethical implications of scientific discovery. His theories on relativity had far-reaching consequences in physics, but the events leading to World War II compelled him to advocate for responsible scientific progress and peace, deeply shaping his later work.