Shucks, Kieth Laumer taught me that, back in '62 or '63.
I was sitting in the shade of a Bolo Mark IV, while it's main batteries cooled down & the infinite repeaters provided automatic air cover for the landing of CDT Peacekeepers and a delegation led by Third Assistant Consul Reteif. With nothing better to do, I pulled out my battered copy of A Trace of Memory, settled down with a bottle of vintage Pepsi, and began reading...