A letter that Albert Einstein penned in 1952 for a Japanese journal has been put up for auction. Titled "On my participation in the atom bomb project," the document details Einstein's thoughts on the global nuclear arms race after being prompted by a magazine editor to defend his support for America's nuclear weapon program during World War II. Einstein was not involved in developing the atomic bomb directly, but in August 1939 he wrote a now-infamous letter to President Franklin D. Roosevelt warning that Adolf Hitler and the Nazi party were likely on the brink of developing atomic weapons. This...