Along these lines, one of the early popular science works is "Letters to a German Princess", which compiles Euler's letters on Natural Philosophy (which is most

Along these lines, one of the early popular science works is "Letters to a German Princess", which compiles Euler's letters on Natural Philosophy (which is mostly what we today call science and maths) which he was commissioned to write as part of her education. Many were keen to educate their daughters as well as royalty, so the book version sold well. It is, of course, very out of date in terms of the science. https://en.wikipedia.org/wiki/Letters_to_a_German_Princess https://en.wikipedia.org/wiki/Letters_to_a_German_Princess