I've been reading Ship of Fools the last few days -- WOW.. FANTASTIC BOOK!!
The Argonos is a space-faring Generation ship containing thousands of humans. The Argonos has presumably been traveling through space for centuries upon centuries. The original goal of the Argonos has been lost over time; no one on board can say for certain of their origins. A class-system has developed in which the commoners and poor serve in the lower levels and provide maintenance for the ship. By contrast, the upper-class maintain positions of power. A Bishop sits as the head of the Church which yields some influence over the people and the Bishop himself is a member of the Executive Council which governs the Argonos. When a signal is received, a team aboard the Argonos prepare to make a landing on the first alien planet which has been encountered in years.