There is a moment in Kevin Costner's Field of Dreams when Doc Graham abandons his dream of playing baseball to walk across the border of heaven and earth to save someone's life. It may be THE moment in the movie, although my son argues that the true moment is when Ray's dad agrees to play a catch. Either way, I leak like a sieve throughout the movie, a timeless film about nostalgia and dreams, and a little about reconciling the losses we have endured. I was five when I decided to become a doctor. There wasn't a moment of wavering from the time my sister was meant to be born in our two bedroom apartment to a midwife (with me watching). Not throughout elementary school, when my friends wanted to be MTV VJs or famous actresses. Not in high school, when I spent every spare moment writing poems and essays and novellas, when my mother urged me to be a writer, to be the next SE Hinton, as if there could be such a thing. And not in college, when I took eighteen cred...