The Slate Stephens series does not have a new book coming out soon. The latest book, Hangman's Gold (Book 2), was published in November 2011.
The first book in the Slate Stephens series, The Governor's Dog Is Missing, was published in February 2011.
The Slate Stephens series primarily falls into the Mystery genre. This middle grade series was written for ages 8-12, but can be enjoyed by older readers as well.