i LOVED these books as a child!
i was homeschooled, pretty sheltered, a few years ahead in school, and not allowed to watch tv... needless to say, a significant percentage of my free time was spent reading.
fortunately, i loved to read, so this wasn't a problem. when i was around six or seven, i realized that seeing as my mother was about to have her third kid (we ended up with five), most of my toys (including my books) were destined for the hand-me-down pile.
so, i made a box of books that i wanted to keep. i just went down to my garage and the great brain and the great brain is back were in there...
i love it.
these books are forty years old and they still make me want to live life awesome.