Homes like this plan were often called tri- or split-levels. Some appear in plan books before WWII, but after the war the style becomes much more prevalent. It's a very modern design that incorporates the garage into the main house; an innovation that didn't commonly occur until after 1950 and then not as a prominent element. The front-and-center garage is seen much more often in middle-class homes after 1955.
© 2011 — Mid Century Home Style