A great place to find older, unique and usual cookbooks is your local goodwill/Salvation Army/thrift store. I picked up a few cookbooks from there not too long ago, and they had some great recipes that were simple to make.
It must be pretty hit and miss, then. I came up with a few great gems from the 70s and 80s. It's interesting to see just how much tastes have changed over the years.
I have picked up some of those wonderful cookbooks from the Fifites, with the detailed recipes and the pages where they show several of the recipes laid out on the family table for dinnertime. Thrift shops are great sources for them, as well as yard sales and estate sales.