These played at the very beginning of each episode over a clip montage in an effort to introduce the show. The original monologue, spoken by Book, was replaced after a few episodes by a different version spoken by Mal that better introduced the characters.
"After the Earth was used up, we found a new solar system and hundreds of new Earths were terraformed and colonized. The central planets formed the Alliance and decided all the planets had to join under their rule. There was some disagreement on that point. After the War, many of the Independents who had fought and lost drifted to the edges of the system, far from Alliance control. Out here, people struggle to get by with the most basic technologies. A ship would bring you work, a gun would help you keep it. A captain's goal was simple: find a crew, find a job, keep flying."
"Here's how it is: Earth got used up, so we terraformed a whole new galaxy of Earths, some rich and flush with new technologies, some not so much. Central Planets, thems formed the Alliance, waged war to bring everyone under their rule; a few idiots tried to fight it, among them myself. I'm Malcolm Reynolds, captain of Serenity. She's a transport ship, Firefly class. Got a good crew: fighters, pilot, mechanic. We even picked up a preacher for some reason, and a bona fide companion. There's a doctor, too, took his genius sister outta some Alliance camp, so they're keeping a low profile. You understand. You got a job, we can do it. Don't much care what it is."