Allegory to what?

The Hitchhiker's Guide to the Galaxy is an allegory to human communication and travel. Many creatures and objects point to this but none like the actual guide. The Guide is supposed to be like a normal tourist guide to a state or country.It states facts about the people and what they are like, why the location or device is important, and how to handle some situations. Another example is the leech thing that Ford put in Aurthur's ear. It would translate unknown frequencies, much like a translator. Without a translator, we wouldn't understand much of another language so we employ one to help us throughout our travels to foreign countries.