our Britannica was pretty old too- not sure what year though- We also had a Britannica like set of just animals-
Read most of that too - to this day an animal will be shown on TV aND pieces of info/facts about said animal will pop into my head about them- useless knowledge but fun-
We bought our daughter a complete set of new Britannicas in the early 90’s when she started school.
Never opened a single one all the way thru HS....................