Fifty years ago, houses were a lot smaller than they are now. Up in Canada, the Central Mortgage and Housing Corporation (equivalent to the US Freddie Mac) prepared plan books to help Canadians and builders produce efficient, relatively easy-to-build houses. They hired architects, some of them very young, who went on to have successful careers; some are still at it. I have owned a copy of the the 1965 Small House Design book for many years, and have always been impressed with the houses, and thanks to a reader, found a PDF online that everyone can have courtesy of the Canadian government.
We showed a lot of the single-floor plans in an earlier post, but there are also sections on the now virtually extinct split-level designs and also what are called 1-1/2 storey designs, now also nearly extinct.
But those 1-1/2 storey plans are really interesting today for a number of reasons, particularly in this era of aging baby boomers.