The story of Leo Szilard has not been told in its full complexity. This is especially so of the role imagination played in Szilard’s worldview. Szilard, like many other scientists in the mid-twentieth century, worked on the Manhattan Project. Like these other wartime participants, the work and relationships formed during this time greatly influenced his future work. Furthermore, Szilard brought his regret for his role in the development of the atomic bomb into his arguments for peace and scientist involvement in seeking peace through conversations with Russians. Many authors have explained his involvement in the initiation of what became the Manhattan Project and his involvement during the war and petitions on the use of the weapons in Japan. Most frequently he played a supporting role to other scientist-actors of the time, aiding and extending their actions as a part of a larger story in which Szilard did not play a central role. But the story of Szilard is important as it tracks changes in American diplomacy and relations with both Russia and the larger world. Through both his fiction and non-fiction, the stories Szilard presented are both serious and humorous, a direct relation to how Szilard thought about the issues and approached them in daily life. These stories also parallel his interests in science and his desires, or fears, for the potential uses of this research. Szilard was extremely rational and held a large amount of faith in science and the power of scientists and other intellectuals to direct policy. In Szilard’s eyes, if he did not speak out about peace and how it might be achieved, he did not know who else would. This dissertation opens with an outline of Szilard’s core beliefs. The following chapters then expand and comment on these beliefs and provide specific examples. In the second chapter, I explore how Szilard’s arguments changed when the Soviets completed in 1949 what he saw to be inevitable, an atomic bomb and the start of the arms race. Chapter three details Szilard’s perspectives on science and science education and how he thought American education should be conducted in order to produce an educated citizenry. I also use fictional pieces to demonstrate Szilard’s critique of society and fears of where a scientized society could lead. Continuing with the use of fiction, chapter four focuses on Szilard’s satirical short story “The Voice of the Dolphins” to explore his ideas of the future and his vision of an ideal world. I connect this to larger ideas of future planning and the trajectory of his thinking throughout his life. A fifth and final, chapter traces the history of Szilard’s “crusade,” and his creation of a lobby through the Council for a Livable World, which ensured citizen involvement in effecting political change through Congressional elections and still functions today.