Which book is the third in the Oz Series, and is the one which introduces the character Billina? 
Billina:  She is first introduced in "Ozma of Oz" (1907). Ozma of Oz: Ozma of Oz: A Record of Her Adventures with Dorothy Gale of Kansas, Billina the Yellow Hen, the Scarecrow, the Tin Woodman, Tik-Tok, the Cowardly Lion and the Hungry Tiger; Besides Other Good People Too Numerous to Mention Faithfully Recorded Herein published on July 30, 1907, was the third book of L. Frank Baum's Oz series.
i don't know