Among the Mad by Jacqueline Winspear
Its Christmas Eve 1931. On the way to see a client, Maisie Dobbs witnesses a man commit suicide on a busy London street. The following day, the prime ministers office receives a letter threatening a massive loss of life if certain demands are not metand the writer mentions Maisie by name. After being questioned and cleared by Detective Chief Superintendent Robert MacFarlane of Scotland Yards elite Special Branch, she is drawn into MacFarlane's personal fiefdom as a special adviser on the case. Meanwhile, Billy Beale, Maisies trusted assistant, is once again facing tragedy as his wife, who has never recovered from the death of their young daughter, slips further into melancholia's abyss. Soon Maisie becomes involved in a race against time to find a man who proves he has the knowledge and will to inflict death and destruction on thousands of innocent people. And before this harrowing case is over, Maisie must navigate a darkness not encountered since she was a nurse in wards filled with shell-shocked men.
Among the Mad is the sixth installment in the Winspear's award-winning Maisie Dobbs series, following Maisie Dobbs (2003), Birds of a Feather (2004), Pardonable Lies (2005), Messenger of Truth (2006) and An Incomplete Revenge (2008).
One of the things I usually say about this series is that although the books are mystery novels, they are less page-turning whodunits than well-crafted period pieces that happen to be mysteries. Among the Mad is an exception because, while it is a well-crafted period piece, it is also a page-turner. While all the Maisie Dobbs books are psychological (Maisie is both a psychologist and a PI after all), Among the Mad is more of a psychological thriller. This--coupled with the subject matter of its storyline--may bring a new audience to the series.