This first came to my attention as a show on PBS and I was fascinated by it, not only for the subject of poisonings, but also how forensics and medical examiners offices came about.  The book has all the same information but was able to go a little more in depth. A little dry in parts (and I confess, I had to skip over any parts where they talked about using dogs as test subjects; yes I understand the importance but it's something I really don't want to have to think about.) but the case histories were fascinating, compelling and horrifying.  The one story that will always stay with me is about The Radium Girls, a group of young women who were employed painting watch faces with Radium.  One of the first women to die, a woman in her early 20s, had a jaw so degraded that the dentist "lifted it out with his fingers."
 
Try to get that image out of your head.
 
Overall a fantastic, haunting and memorable book and one I recommend to anyone interested in forensics.