3M Bookshelf Series
3M Bookshelf Games is a series of games published by 3M Games from 1962 to 1974. The name for the series was in reference to the slipcase boxes the games came in, which were designed to look like leather-bound books when closed. When 3M closed its game division, the line was sold to Avalon Hill who continued publishing a number of them.
(The Boardgamegeek 3M Bookshelf Series Family)
The original versions of the games had a plain spine, later printings (and the last four 3M games) had fancier spines:
Traditional games in the series