Lesson in Secrets, A (Maisie Dobbs #8) by Jacqueline Winspear; 2012. Softcover.

In the summer of 1932, Maisie Dobbs’s career takes an exciting new turn when she accepts an undercover assignment directed by Scotland Yard’s Special Branch and the Secret Service. Posing as a junior lecturer, she is sent to a private college in Cambridge to monitor any activities, “not in the interests of His Majesty’s Government.”
When the college’s controversial pacifist founder and principal, Greville Liddicote, is murdered, Maisie is directed to stand back as Detective Chief Superintendent Robert MacFarlane and Detective Chief Inspector Richard Stratton spearhead the investigation. She soon discovers, however, that the circumstances of Liddicote’s death appear inextricably linked to the suspicious comings and goings of faculty and students under her surveillance.
To unravel this web, Maisie must overcome a reluctant Secret Service, discover shameful hidden truths about Britain’s conduct during the Great War, and face off against the rising powers of the Nationalsozialistische Deutsche Arbeiterpartei—the Nazi Party—in Britain.
As the storm clouds of World War II gather on the horizon, this pivotal chapter in the life of Maisie Dobbs foreshadows new challenges and powerful enemies facing the psychologist and investigator.