Merry Go Round in Oz (1963) is the fortieth in the series of Oz books created by L. Frank Baum and his successors. It was written by Eloise Jarvis McGraw and Lauren McGraw Wagner (her married name was dropped from reprinted editions after the marriage ended). It was illustrated by Dick Martin. Merry Go Round in Oz is the last of the "Famous Forty" and the last "official" Oz book. Reilly & Lee had declined offers from many other writers, including previous author Rachel R. Cosgrove, to publish a fortieth Oz book because of poor sales, but were persuaded by McGraw's two Newbery Awards to admit a fortieth book into the series. The first edition, the so-called "white edition," is the rarest book in the series in its original printings. Source: Wikipedia (en)