Having studied psychology, and being interested in true crime books I found the premise of this tome intriguing. After a lengthy introduction, and an author’s note reminding me that these stories were written with the UK’s National Health Service and systems. These are useful reminders for context.
At the end of the day, I found the subject matter delivered in a dry and clinical manner. It was not a good fit for my taste.
A copy of The Devil You Know: Stories of Human Cruelty and Compassion was provided to me by NetGalley and Scribner, for an honest review.

I just reviewed The Devil You Know by Gwen Adshead; Eileen Horne. #NetGalley

It is actually fascinating to read the stories of these 'evil' characters, Gwen makes clear that sanity and insanity are near by and you can easily see how our brains sometimes misbehave leading to the most outrageous crimes and heinous acts. You may still not want to have one of the 'Devils' living next to you, but you certainly understand how they became and you may even be able to relate. The book is a great contribution to a more peaceful society.