Yes, I followed your rabbit trail over to Prof Davies! Then I got to worrying maybe it was an imposter, but I messaged him on Facebook, and it's him! So that's really cool. I wish more of my econ friends would come over here. Cost Benefit Jr was written for my 8 yo son, but I actually didn't teach it to him until his senior year of high school. It's written for a very young audience, but honestly, some of the economic concepts in there need to be explained in that way, even for adults.