Which Narnia book begins with four siblings entering another world through a wardrobe?

The Narnia book in which four siblings enter another world through a wardrobe is The Lion, the Witch and the Wardrobe. Published in 1950, it follows Peter, Susan, Edmund, and Lucy Pevensie after Lucy discovers a passage from a country house into Narnia.

Lucy first encounters the faun Mr. Tumnus, while the land is under the rule of the White Witch. The children later meet Aslan and become involved in the conflict that ends the Witch’s winter regime. The wardrobe is the story’s most recognizable gateway and gives the book its distinctive opening premise.

Although it is the first Narnia book published, it is sometimes listed second in proposed chronological reading orders. The Magician’s Nephew, published later, describes events that occur earlier in Narnian history. That difference between publication order and internal chronology is a frequent source of confusion.