The Melendy Quartet series does not have a new book coming out soon. The latest book, Spiderweb for Two (Book 4), was published in August 1987.
The first book in the Melendy Quartet series, The Saturdays, was published in January 1941.
The Melendy Quartet series primarily falls into the General Fiction genre. This middle grade series was written for ages 8-12, but can be enjoyed by older readers as well.