There are 4 books in The Underworld Chronicles series.
The Underworld Chronicles series does not have a new book coming out soon. The latest book, Elliot and the Yeti Threat (Book 3), was published in April 2012.
The first book in The Underworld Chronicles series, Elliot and the Goblin War, was published in October 2010.
The Underworld Chronicles series primarily falls into the Fantasy genre. This middle grade series was written for ages 8-12, but can be enjoyed by older readers as well.