The Time Navigators series does not have a new book coming out soon. The latest book, Race Against Time (Book 3), was published in January 1997.
The first book in the Time Navigators series, The Dangerous Voyage, was published in September 1995.
The Time Navigators series primarily falls into the Christian Fantasy genre. This middle grade series was written for ages 8-12, but can be enjoyed by older readers as well.