The Byworlder (Signet)
by Poul Anderson
Category: Human-alien encounters

The first emissary from interstellar space has been in orbit for three years and still no one knows how to comminicate with it or why it had come to Earth from Sigma Draconis. But then Skip Wayburn, an otherwise ordinary "byworlder" (a person who has opted out of life in mainstream society) suddenly knows why the ship had come and what it wanted. But how will he make anyone take him seriously?