There are 2 books in the Double R Detectives series.
The Double R Detectives series does not have a new book coming out soon. The latest book, The UFO Mystery (Book 2), was published in January 1995.
The first book in the Double R Detectives series, The Case of the Dude Ranch Rustlers, was published in January 1995.
The Double R Detectives 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.