Just found on this excellent post @ Urban Retro — a Flickr set of Frank Soltesz 1940s cutaway illustrations from the Saturday Evening Post. Well worth clicking through, each one is a hi-res scan of a painstakingly beautiful industry (like dry goods or medical) illustration and a complete article describing how these building-systems worked. I especially love this department store illus, the hospital, and the air conditioning system in a theatre. If you like this, also see Urban Retro’s post on the fantastic 60s sci-fi cross-section illustrations of Graham Bleathman.