"Family stories grow to be bigger than the experiences themselves," writes Judy Goldman in her memoir, Losing My Sister . "They become home to us, tell us who we are, who we want to be. Over the years, they take on more and more embellishments and adornments until they eclipse the actual memory. They become our past--just as a snapshot will, at first, enhance a memory, then replace it." As she remembers it now, Goldman's was an idyllic childhood,...