“Our baby won’t sleep and we’ve been up all night for the past 6 months. Nothing works! We’ve tried ignoring the crying, rocking him back to sleep, and riding in the car for hours on end. We’re exhausted, at our wit’s end, and nobody is functioning in the house. We can’t go on another day like this. Please help us!” These could be the words of many families who have struggled with a sleepless baby. For many parents, solving the child’s sleep problems is extremely challenging, and therefore it is important to understand the complexities that underlie falling and staying asleep.