The Oz books

L. Frank Baum: The Oz books: 
The Wonderful Wizard of Oz (1900)
The Marvelous Land of Oz (1904)
Ozma of Oz (1907)
Dorothy and the Wizard in Oz (1908)
The Road to Oz (1909)
The Emerald City of Oz (1910)
The Patchwork Girl of Oz (1913)
Tik-Tok of Oz (1914)
The Scarecrow of Oz (1915)
Rinkitink in Oz (1916)
The Lost Princess of Oz (1917)
The Tin Woodman of Oz (1918)
The Magic of Oz (1919)
Glinda of Oz (1920)

Lyman Frank Baum (1856–1919) was an American author, actor, and independent filmmaker best known as the creator, along with illustrator W. W. Denslow, of one of the most popular books ever written in American children's literature, The Wonderful Wizard of Oz, better known today as simply The Wizard of Oz. He wrote thirteen sequels, nine other fantasy novels, and a plethora of other works, and made numerous attempts to bring his works to the stage and screen. (Wikipedia)
The fourteen Oz books, written during the two first decades of the last century, form a corpus of its own. To this corpus could be added a couple of books not set in the magical land of Oz, but whose heroes and heroines later figure in Oz books, as well - The Sea Fairies (1911) and Sky Island (1912).

These books are, of course, aimed at children. A true adult, however, is a person who retains many positive childish properties, while discarding the negative ones. Therefore, the Oz books can very well be used as light reading by adults as well. They are charming and have been purged of the darker elements of earlier fairy tales (e.g. the violence of the brothers Grimm stories).
At the same time, there is a strong moral element in the Oz books. The fight between good and evil has perhaps been scaled down to a struggle between naughty and nice, but it is there, nevertheless. The place of females (not women so much as girls, but anyway) is much more emancipated than one could expect from stories a century old - queens and generals, and of course Ozma and Glinda, are often female along with male rulers such as his imperial majesty the Tin Woodman.

I cordially recommend the Oz books for any child or (true) adult who wishes to be entertained and excited, but not horrified. I've used them as bedtime stories for my childish self, and enjoyed them all!