“Billie lies awake for a long time, watching the passing lights of cars on the highway and thinking about a strange phenomenon the French call l’appel du vide, the call of the void. It’s when you stand up high, staring into an abyss, and have a strong desire to throw yourself into it. It can take other forms. You might be driving and suddenly think about jerking the wheel, sending your car into oncoming traffic. Or you might be out for a hike and fantasize about hurling yourself off a cliff. It is not a suicidal impulse. In fact, it is the opposite. Psychologists say it’s actually about how much a person wants to live. They perceive a nearby threat to themselves and they think about that threat because they want so much to survive.”