Question: Which book is the third in the Oz Series, and is the one which introduces the character Billina? 
Sentence (from "Rinkitink in Oz"): Published on June 20, 1916, with full-color and black-and-white illustrations by artist John R. Neill, it is significant that no one from Oz appears in the book until its climax; this is due to Baum's having originally written most of the book as an original fantasy novel over ten years earlier, in 1905.
Relevant evidence: No