This advert in TV21 from March 1968 jogged my memory. I had the book A Pageant of History! I had a few like that I think, part of the Collins Pageant of Knowledge series. They could still be in my attic! they weren't from TV 21 though. My Folks will have bought them at Sweeten's bookshop in Preston town centre back then I reckon. Maybe other stores like BHS and Owen and Owen too.
Here's the book in colour!
Did you have one readers?