I have long held a fascination with the concept of fallout shelters and the graphic design behind encouraging people to be prepared for a nuclear holocaust. It is definitely worth your time to read the in-depth discussion about the design of the famous yellow/black logo .
One of my favorite publications from the era is Fallout Protection: What to Know and Do About Nuclear Attack. The image here are scanned from my copy. Check out this lengthy page about the history of this particular publication. There is not a lot of information about the design thinking/process behind this publication or any of the others, but there is much that can be interpreted.
The design and illustrations of these pamphlets and posters of this era mostly all struggled with the challenge of conveying information without scaring the crap out of the readers. And, because the the US population was already scared, I’m certain this was a challenge. The illustration style is simple, but conveys much information, often in a wireframe-like appearance. This style was common in both advertising and fashion in the 1950s and early 1960s. Unsurprisingly, there is no ethnic diversity of people depicted. The use of a secondary color was also common for this kind of pamphlet, and is reminiscent of church flyers and bibles of the era. The color is used for shading and most of the time there’s a feeling that the designer was using color just to use color to make the illustrations pop. A classic typographic mix of the era, and still common today, sans-serif headlines with serif text.
A great source for more info: Trinity Atomic Web Site