McDermid is definitely an adult market author. This series, the Tony Hill/Carol Jordon, are detective/psychological thriller novels. Hill is a clinical psychologist/serial murderer profiler who has a close friendship with UK police detective Carol Jordon.
The Last Temptation is set primarily in the Netherlands and Germany. In this novel Carol Jordon goes undercover in the attempt to acquire incriminating evidence about an arms/dealer and human labor smuggler. To add to the complexity of her situation, she and her European colleagues also come across a serial killer working from a boat working the Rhine river. It is compelling--the action, as always in McDermid's books, is intense. I recommend against picking up these books when you have work or family pressures. You'll end up reading too long.
McDermid's books are not for the faint of heart. They typically include violence and sexual themes--often linked. Although she does not include salacious details, the settings and events are powerful enough to leave an imprint. She has been a journalist but became a full time novelist in 1991. She was born in Scotland and continues to live there. (See her website: http://www.valmcdermid.com/) She has won many awards, her Tony Hill/Carol Jordon books were also made into a TV series Wire in the Blood.
Her writing feels sophisticated to me. I end up researching parts of Scotland, England (and in this book Germany and The Netherlands) as well as reading with my smartphone close at hand so that I can look up words on The Free Dictionary.
I'm finishing the series. I've just completed The Torment of Others and am back-tracking to read Wire in the Blood . I am visiting the Netherlands and Scotland this summer. I've been trying to do some of my reading in books set in those areas (recommendations would be welcome!).