Scene-Setting

The opening pages or paragraphs of a work of futuristic science fiction set the scene by referring to unfamiliar aspects of a future society that we will come to understand as we read further. Thus, in Poul Anderson's Three Worlds To Conquer, a space battleship, the USS Vega:

"'...was on patrol near Venus when the revolution broke, and was put to searching for an orbital base the Sam Halls were believed to have somewhere in that sector.'"
-Poul Anderson, Three Worlds To Conquer (London, 1966), Chapter 1, p. 8.

OK. Sf readers catch on fast:

there is regular interplanetary travel;
the United States still exist;
there has just been a revolution;
the revolutionaries were nicknamed the "Sam Halls"?

Yes. In fact, there had been a short story about the Sam Halls' revolution (see here) although I did not learn this until many years later.

Incidentally, my copy of Three Worlds To Conquer is a "Mayflower-Dell Paperback." I am much indebted to Mayflower-Dell because the first James Blish novel that I read was their edition of Earthman, Come Home. For many years, Blish was superior to Anderson in my estimation. I have come to appreciate Anderson considerably more than I did and, of course, his output was much bigger.