E-054 Three Worlds Carrying Case Set
General Information
The following information has been collected from original newspapers, catalogs, and magazines, some of which are freely available for reference below. The rest can be found in the site’s gallery. No aggregate catalogs (BrickLink, Brickset, etc.) were used.
Advertised Part Count(s): 607 pieces
First Year Confirmed Available: 1968(USA)
USA Only.
Most Likely Retirement Date: 1969(USA)
It reappears in the 1969 Three Worlds Catalog.
As Three Worlds was defunct by early 1970, the latest retirement date would be 1969.
Last Year Seen Available: 1969
Aliases: 607-Piece Lego Set in Three Worlds Carrying Case
Retail Price(s): $20.00(USA)
Rarity Score(Index): 8/7
Only two examples are currently known, hence the 8/7.
Box/Overview
I originally purchased my Three Worlds catalog to find out the date that the T-014 set released for What was Three Worlds Inc.?. Before putting it away, however, I decided to take a peek through and stumbled upon the listing below:

I'd never seen the set before. I was familiar with the Loveland case and that some sets had used it, but I hadn't yet gone through the trouble of sorting them all out so I wasn't sure what I was looking at.
I reached out to a collector that had offered to help me previously and they fortunately happened to have a copy. You can see an image of the set's exclusive(and quite beautiful) turquoise case on Daan's flickr.
About the only other notable thing left for the overview is that the 'E' in E-054 means "Elementary" according to the catalog.
Contents
Interestingly, the set's models are seemingly the exact models on the back of the 615 Basic Set(and by extension the 630 Diplomat Set, as the 630 reused the 615's box):


I wasn't the one who noticed this, Daan made the connection as a possibility for where the set's inventory derived from.
Because the Diplomat set was released in 1970, two years after the E-054, it is very likely it contained nearly the same assortment as the 615 instead. But there are some stipulations.
There's a lot to cover, so I plan to do so in a future article.