Since I was able to find out the series of those books I was talking about I ordered a couple. They are long out of print, but they were ubiquitous enough that copies survive in the wild that aren’t expensive second hand. Unfortunately the exact book I was thinking of is $70 assuming you can actually find a copy, so it’s only a partial victory. I’m going to keep my eye out for the others and see if I can get ahold of others if I can. The publisher still exists, but they are very child centric now & have lost what made their content interesting in favor of selling to a broad audience. I don’t begrudge them that. I know very well how hard it is to market something that isn’t for general audiences. It is sad though. A unique style was lost in favor of sales.