From the time Kim Crabill experienced a life-altering trauma at age four, she became an expert in hiding her hurt and confusion behind a mask. The trick, she discovered, was to sing a little louder in choir, study a little harder at school, and smile a little wider with friends. Then no one would notice how damaged her heart was. Kim became a classic overachiever academically and socially. As an adult, she could even speak before...