Concord writer Gregory Maguire has announced that he’ll release a book this fall that draws the curtain on his highly popular “Wicked’’ series. “Out of Oz,’’ which hits shelves Nov. 1, was mostly written at Maguire’s home in Concord, where he lives with his husband, painter Andy Newman, and their three kids. The book weighs in at 550 pages and will contain three maps of Maguire’s Oz universe. The author told us today that he kept this last book under wraps during much of the writing process, just in case it didn’t work out — or he changed his mind. He also told us that he named the book before writing it, and that the title is a nod to “Out of Africa,’’ as well as an announcement of the end of the series, which spawned 1995’s “Wicked,’’ 2005’s “Son of a Witch,’’ and 2008’s “A Lion Among Men.’’ “Look folks,’’ Maguire told us, with a laugh, “I’m out of here. I’m done.’’ He promises that the last book will keep Oz as it has been in his other novels — a gritty, political, sexual place where magic is possible. “People actually go to the bathroom,’’ he said, of his Oz. “There is sexual disfunction.’’ He added that “Out of Oz’’ is as close to “Gone With the Wind’’ as a “Wicked’’ book can get. Sounds good to us.