My parents also bought a set of World Book encyclopedias in about 1963 or 64. I can't remember which but it was about that time (I was born in 1959). I have no idea what Dad paid for them but I think between then and my leaving home I read every word in them - especially anything to do with any war, airplanes, or farming. My parents must have been doing pretty well during those years because within about a three year period they bought the encyclopedias (and the yearly update book until sometime in the 80s), a full set of Saladmaster cookware, a new bedroom set, a new living room set, a brand new JD 3010 diesel along with a new 12' RWA disk and 4 row Ford planter, and the neighboring farm. Of course, I'm also sure that Dad took on a lot of debt in order to do all that.