Which C.S. Lewis book introduces the fictional land of Narnia?

The Lion, the Witch and the Wardrobe introduces the fictional land of Narnia in C.S. Lewis’s Chronicles of Narnia.

Published in 1950, the book follows Peter, Susan, Edmund, and Lucy Pevensie after Lucy discovers a passage into Narnia through a wardrobe. There they encounter the White Witch and the lion Aslan, whose return begins the story’s central conflict.

Prince Caspian was published next, in 1951, although some editions arrange the books according to the internal chronology of Narnian history. That difference causes occasional confusion about which book comes first. The wardrobe story is the first Narnia book Lewis published.

Lewis drew on fairy tales, medieval imagery, classical mythology, and Christian ideas. He did not write the series as a straightforward retelling of the Bible; instead, its symbolism works through an original fantasy world.