After Jonni and I had finished reading the Great Brain books, and I was utterly sick of reading them out loud, Jonni took to reading them on her own.
These books are not all that easy to find. I believe they are possibly out of print. It took me a couple years, literally, of rooting though used book stores, trash cans, Jawa transport vehicles, Goodwills, etc before I could amass all 8 in paperback. Even then, in the end I was forced to buy the 8th (and rarest) book of the series online. (I am rich and could afford to buy them the normal way, but that takes all the fun out of it for me.)
Well, it took Jonni a couple of weeks, literally, to trash the bindings on most of my cautiously horded Great Brains. Bah!
So, it was a thrill, when she and me were at the local library this week and found ALL EIGHT OF THEM, in hardback, good condition for 50 cents each! We wasted no time accelerating from sight to ownership. Mine! all Mine! bwahahahaha! Suckers!
Also this week, I bought Carl Sagan's Cosmos, orginally $35 US back in 1980. Seventy-five cents, lightly used. heheheh.
Snagged a couple more Asimov books from the Foundation series too, for a quarter or so. Think I have all of them now.