Albert Einstein remarked towards the end of his career that he only went to his office at Princeton 'just to have the privilege of walking home with Kurt Godel'. They had both fled Europe and the clutches of Nazism and found rare solace in each other's company in foreign exile. Godel was one of the few people to understand the philosophical implications of Einstein's theories of the universe – and would later honour Einstein's seventieth birthday by addressing his theories directly, proving time to be an ideal. This extraordinary friendship is one of the most remarkable of the twentieth century.