" How can trade be bad if you don’t make money
even when it’s good?” inquired Gleed, reasonably
applying the information Harrison had given him.
Jeff’s big moon eyes went over him slowly then
turned to Harrison. “So he’s another bum off your
boat, eh? What’s he talking about?”
“Money,” explained Harrison. “It’s stuff we use to
simplify trade. It’s printed stuff, like documentary
obs of various sizes.”
“That tells me a lot,” Jeff Baines observed. “It
tells a crowd that has to make a printed record of
every ob is not to be trusted — because they don’t
even trust each other. "

― Eric Frank Russell , The Great Explosion