Adding to the list - The Fold by Peter Clines. It came out this week and I loved it. It’s a stand-alone novel, sortta as it is adjecent to another one of his novels, 14. They are both worth a read but you don’t need to have read 14 to thoroughly enjoy The Fold.

I am a great fan of the Mary Russell series. Thanks for pointing out the other worka as I wasn't familiar with them.