Over the course of more than ten years, a mysterious and violent predator committed fifty sexual assaults in Northern California before moving south, where he perpetrated ten sadistic murders. In 1986 he disappeared, eluding capture by multiple police forces and some of the best detectives in the area. At the time of the crimes, the man journalist Michelle McNamara dubbed the Golden State Killer was between the ages of eighteen and thirty. He always wore a mask. He attacked while his victims slept, using a flashlight to awaken and blind them. Though they could not recognize him, his victims recalled his voice: a guttural whisper through clenched teeth. I'll Be Gone in the Dark-the masterpiece McNamara was writing when she died tragically at the age of forty-six-offers an atmospheric snapshot of a moment in American history and a chilling account of a criminal mastermind and the wreckage he left behind. It is also a stunning portrait of a woman's obsession and her unflagging pursuit of the truth.