I have a U.S. Political History textbook (highschool level I believe) from 1949. The first page after the table of contents features a picture of a mushroom cloud from a nuclear explosion, and a blurb about how the U.S.A. created an ultimate weapon that saved the lives of millions by forcing Japan to make peace. It was such a shock opening to that page the first time I opened the book... Understandable that the myth has propagated for so long; we were indoctrinating our children with this misinformation.