Kristina Olsson's mother lost her infant son, Peter, when he was snatched from her arms as she boarded a train in the hot summer of 1950. Yvonne was young and frightened, trying to escape a brutal marriage, but despite the violence and cruelty she'd endured, she was not prepared for this final blow, this breathtaking punishment. Yvonne would not see her son again for nearly forty years. Kristina was the first child of her mother's subsequent, much gentler marriage and, like her siblings, grew up unaware of the reasons behind her mother's sorrow, though Peter's absence resounded through the family, marking each one. Yvonne dreamt of her son by day and by night, while Peter grew up a thousand miles and a lifetime away, dreaming of his missing mother. Boy, Lost tells how their lives proceeded from that shattering moment, the grief and shame that stalked them, what they lost and what they salvaged. But it is also the story of a family, the cascade of grief and guilt through generations, and the endurance of memory and faith.