There are 3 books in the Miss Hart and Miss Hunter Investigate series.
The Miss Hart and Miss Hunter Investigate series does not have a new book coming out soon. The latest book, The Hidden House Murders (Book 3), was published in September 2017.
The first book in the Miss Hart and Miss Hunter Investigate series, Murder at Merisham Lodge, was published in February 2016.
The Miss Hart and Miss Hunter Investigate series primarily falls into the Historical Mystery genre.