The novel begins with a prologue called "Semley's Necklace", which was previously published as a stand-alone story. A young woman named Semley takes a space voyage from her unnamed planet to a museum to reclaim a family heirloom. The novel then follows Rocannon, an ethnologist who meets Semley at the museum and later comes to her planet to explore it. After an enemy of the League of All Worlds destroys his ship and his companions, he sets out to seek revenge.
The story has strong resemblances to heroic fantasy, as Semley's people include lords in castles with swords, and other races on her planet are much like fairies and gnomes. Rocannon meets many colorful creatures in his travels.
Rocannon's World was republished in 1978 along with Planet of Exile and City of Illusions in a volume called Three Hainish Novels and in 1994 with the same novels in Worlds of Exile and Illusion.