Who is the author of nania?

You're likely referring to "Narnia," which is a series of fantasy novels written by C.S. Lewis.

The full title of the series is "The Chronicles of Narnia," and it consists of seven books:

* The Lion, the Witch and the Wardrobe (1950)

* Prince Caspian (1951)

* The Voyage of the Dawn Treader (1952)

* The Silver Chair (1953)

* The Horse and His Boy (1954)

* The Magician's Nephew (1955)

* The Last Battle (1956)