At this point in time she has written the following books
Outlander (also released as Cross Stitch)
Dragonfly in Amber
Voyager
Drums of Autumn
The Outlandish Companion
The Fiery Cross
Lord John and the Private Matter
A Breath of Snow and Ashes
All of these books are part of the Outlander series except for Lord John and the Private Matter. It is actually a spin off of one of the characters from the Outlander series.
This series is utterly amazing. It's an amazing tale of time travel embedded with romance and a whole lot of historical detail. Claire Randall falls through time to 1761, right in the middle of Scotland. Right before the Jacobite Rising. Diana weaves you into the story so well, you feel like you're right in the middle of it. She tells you what Claire does to survive, how she adapts to her surrondings despite how different it is. There's romance, war, family values, everything in these novels. She went so far to make it to where all of her facts were right. The historical detail is unreal. It almost makes it feel like an interesting history book. There is no doubt at how much work she put into these novels. Of course because of the work they are also rather long. Outlander is 800+ pages and the later ones are upwards of 1100+ pages. She was so detailed in her work that she ended up with a lot of information. And to give us readers who are so hooked on her work more of a fix she released The Outlandish Companion which is actually a book dedicated to even more historical detail to let us know where she pulled her facts from.
Anyone that loves historical romance, or just a good novel will love this series. You must also be able to tolerate the longer novels. In fact, Diana has even said that she wrote Lord John and the Private Matter just to see if she could write a shorter book.
Feel free to ask any questions. I don't know anything about her newest book but I will soon. I'm almost to the point of starting on it. At least look it up online and read in better detail what it's about.