The Horse and His Boy is a fantasy novel for children by C. S. Lewis, published by Geoffrey Bles in 1954. Of the seven novels that comprise The Chronicles of Narnia (1950–1956), The Horse and His Boy was the fifth to be published. The novel is set in the period covered by the last chapter of The Lion, the Witch, and the Wardrobe during the reign of the four Pevensie children as Kings and Queens of Narnia. Though three of the Pevensies appear as minor characters in The Horse and His Boy, the main characters are two children and two talking horses who escape from Calormen and travel north into Narnia. On their journey, they learn of the Prince of Calormen's plan to attack Archenland, and warn the King of Archenland of the impending strike.

Susan Pevensie is a fictional character in C. S. Lewis's The Chronicles of Narnia series. Susan is the elder sister and the second eldest Pevensie child. She appears in three of the seven books—as a child in The Lion, the Witch and the Wardrobe and Prince Caspian, and as an adult in The Horse and His Boy. She is also mentioned in The Voyage of the Dawn Treader and The Last Battle. During her reign at the Narnian capital of Cair Paravel, she is known as Queen Susan the Gentle or Queen Susan of the Horn. She was the only Pevensie that survived the train crash on Earth which sent the others to Narnia after The Last Battle.