The Underground will be released by Blaze Publishing on 9/12/17! Make sure to grab your copies!
You can purchase the book here:
https://www.google.com/url?hl=en&q=https://www.blazepub.com/books/the-underground/&source=gmail&ust=1503425670461000&usg=AFQjCNG6mgiGgK4J6CbyQ8aZ1070odXq1g