According to the Experts, you must always start your story “in media res” or in the middle of the action. That particular rule is driven hard at newbie writers, who are more likely to start by laying some groundwork. A good writer will begin in the middle of the crisis, make it worse, then fix it… slowly, with many setbacks. That is supposed to be The Way to write a good story.
There is something to that rule. In my slush pile sorting adventures, I have read – or tried to read, anyway – many slow starters. Generally speaking, I much prefer a quicker start, but there is a time and place for slow movers.
Many of the Hugos and Nebulas I read had opening paragraphs, scenes, or chapters that would move backwards if they went any slower. You’ve seen quicker dead sloths, I’m sure. Some of the tales started with long blocks of backstory or character details or world building. If there was any action, it was sparsely interlaced with the other data. Apparently, if these tales are considered the best science-fiction has to offer, a slow starter is acceptable, regardless of the admonition of The Rules.
So, what should we do? Engage your reader quickly, but if you need some background information to keep things clear, that’s okay. Just be sure that your addition actually serves the story. Famous examples of the practice are not a license for sloppiness.