Which C.S. Lewis book was first published in 1950 and introduces the wardrobe portal to Narnia?

The Lion, the Witch and the Wardrobe was first published in 1950 and introduces the wardrobe portal to Narnia.

The story follows Peter, Susan, Edmund, and Lucy Pevensie, who discover a passage from a country house into the magical land of Narnia. Lucy is the first sibling to enter through the wardrobe. In Narnia, the children encounter the faun Mr. Tumnus, the White Witch, and the lion Aslan.

The book was the first Narnia novel released, although Lewis later wrote The Magician’s Nephew as a prequel in internal chronology. Its title is sometimes shortened informally to “The Lion, the Witch and the Wardrobe,” but the full title includes all three central images.