Among the Mad by Jackquline Windspear (2009)

This must be my third Maisie Dobbs book, and for some reason I don't care if I read them in order. This one is set in 1931 and Maisie has her own investigative business with one assistant. It is at the end of December in 1931. She sees a man blow himself up on a London street. Then the Prime Minister receives a threatening letter promising loss of many lives if the soldiers of the Great War are not taken care of. The letter mentions Maisie, so she is called in to a special branch of Scotland Yard to help. She provides insights that help solve the case and stop the mad man from completing his plans.

The focus in this book is on PTSD or shell shock after the war. Not only are many of the men who served in the military affected, but almost everyone is affected, including Maisie herself. But the theme is woven through many people's stories, including her friend, who is financially sound, has a husband and kids, but still despairs at times. Her assistant's wife is unstable after the loss of one of her children, and through her experience we see some of the horrors of the way some mental patients were treated in those days. We also see the aftereffects of the chemical warfare experiments, where the researchers sometimes tested the substances on themselves and other workers. Again, more details fleshing out that time period and the continued growth of Maisie, as she forges ahead with her life.