Luke McCallin's experiences working for the United Nations as a humanitarian relief worker and peacekeeper in the Caucasus, the Sahel and the Balkans have driven his writing, in which he explores what happens to normal people-those stricken by conflict, by disaster-put under abnormal pressures. His experiences also inspired a historical mystery series with an unlikely protagonist: Gregor Reinhardt, German intelligence officer and former Berlin detective chased out of the police by the Nazis.

The Man From Berlin and The Pale House were both set in Sarajevo during WWII. The Divided City followed Reinhardt's return home to Allied occupation, and a serial killer loose in the rubble.