An engaging modern-day thriller, “Shadow of Doubt” features a young female banker embroiled in terrorism, a deteriorating marriage, and a mysterious legacy, all of it intertwined and gradually accelerating. A fast-paced, likeable read whose tension does not quite match the plot’s gravity, the book whiles away an evening with its diligent, rather gormless heroine and well drawn city and rural locales. An assured debut that hopefully will spawn a series.