When television producers approached Alan Cumming to appear on a popular celebrity genealogy show, he hoped to solve the mystery of his maternal grandfather's disappearance that had long cast a shadow over his family. But this was not the only mystery laid before Alan.

Alan grew up in the grip of a man who held his family hostage, someone who meted out violence with a frightening ease, who waged a silent war with himself that sometimes spilled over onto everyone around him. That man was Alex Cumming, Alan's father, whom Alan had not seen or spoken to for more than a decade when he reconnected just before filming for Who Do You Think You Are? began. He had a secret he had to share, one that would shock his son to his very core and set into motion a journey that would change Alan's life forever.

With ribald humor, wit, and incredible insight, Alan seamlessly moves back and forth in time, integrating stories from his childhood in Scotland and his experiences today as the celebrated actor of film, television, and stage. At times suspenseful, at times deeply moving, but always incredibly brave and honest, Not My Father's Son is a powerful story of embracing the best aspects of the past and triumphantly pushing the darkness aside.