There are 2 books in the Four Horsemen of the Highlands series.
The Four Horsemen of the Highlands series does not have a new book coming out soon. The latest book, Wager with a Warrior (Book 2), was published in August 2020.
The first book in the Four Horsemen of the Highlands series, Ensnared by the Laird, was published in April 2020.
The Four Horsemen of the Highlands series primarily falls into the Historical Romance genre.