Mia Hamm, the greatest female soccer star of her time, says it straight out. “All my life I’ve been playing up, meaning I’ve challenged myself with players older, bigger, more skillful, more experienced—in short, better than me.” First she played with her older brother. Then at ten, she joined the eleven-year-old boys’ team. Then she threw herself into the number one college team in the United States. “Each day I attempted to play up to their level…and I was improving faster than I ever dreamed possible.”