Nightwings

Nightwings is a science fiction novella by the American writer Robert Silverberg, first published in Galaxy Science Fiction in September 1968. It won the Hugo Award for Best Novella in 1969 and the Prix Apollo in 1976.

It is set in a decadent future in which humanity is divided into guilds, each of which has a particular job, and in which at least some of the guilds have been genetically altered to do it: the Fliers can fly, and the Watchers have the equipment and the ability to watch distant stars and report to the Defenders if there is an invasion.

The narrator is a Watcher, and he travels to the ancient city of Roum, thought to have once been called Rome, in the company of a young woman of the Fliers and a Changeling, who belongs to no guild at all. In Roum he becomes caught up in events that include the possibility of an invasion. It is the first of three linked novellas about him, and the three were later collected into a single novel under the same title.