Thanks! Interesting. I met Azimov at a book party many years ago. Times were so different then. SF was a backwater. Azimov probably made his livng writing non-fiction science works. He was admired for putting out a book a week, or something close. I remember having his various science books. In doing that, he was knowledgeable about any subject yoiu could put in a book, from economics to nuclear physics.