During World War II, millions of Americans who had never travelled beyond their own states were, in short order, trained and sent far away to foreign lands filled with people very different from themselves. So the Army published a series of guidebooks that taught the Americans how they should conduct themselves in ways that would leave the natives with the right impression. These books included the nations of France, Britain, Australia, Germany, Iran, and Iraq.
(Images: US Army/Amazon.com)
They included helpful pointers on etiquette. For example, don't slap an Iraqi on the back. You may think of it as a friendly gesture, but the average Iraqi won't. You can read more about these guides at Atlas Obscura.
-via VA Viper