There are 6 books in the Jeffrey and the Fourth-Grade Ghost series.
The Jeffrey and the Fourth-Grade Ghost series does not have a new book coming out soon. The latest book, Big Brother Blues (Book 6), was published in June 1990.
The first book in the Jeffrey and the Fourth-Grade Ghost series, Max is Back, was published in September 1989.
The Jeffrey and the Fourth-Grade Ghost series primarily falls into the Fantasy genre. This chapter book series was written for ages 7-10, but some older readers may still like to read these books.