Rep. Gabrielle Giffords vows to return to Congress in a new book that details months of intense therapy and her emotional battle to come to terms with what happened when a gunman opened fire in front of a Tucson grocery store. The memoir, titled "Gabby: A Story of Courage and Hope," is the most personal and detailed look yet at Giffords' efforts over the past 10 months to relearn how to walk and talk, and her painful discovery that six people were killed in the Jan. 8 attack outside a Tucson grocery store.