Question: How many books in the wizard of oz?
Disambiguated questions and answers: question: How many books are in the original and canonical Oz books by L. Frank Baum?
How many books are in the Wizard of Oz, including all story compilations?
How many books are in the Wizard of Oz, including all story compilations and works that are not Oz stories, but are set in the same universe and contain character crossovers?
answer: 14
18
24
Natural Questions answer: fourteen (from the Wikipedia article "List of Oz books")