The Summer Island series does not have a new book coming out soon. The latest book, A Tiara for the Taking (Book 4), was published in June 2012.
The first book in the Summer Island series, A Prince in Peril, was published in May 2009.
The Summer Island series primarily falls into the Action Adventure genre. This middle grade series was written for ages 8-12, but can be enjoyed by older readers as well.