On March 30, 1908, Chester Gillette, 25, was executed at Auburn State Prison in New York for the murder of his pregnant lover, Grace Brown, on an Adirondack lake in 1906. His sensational trial inspired the Theodore Dreiser novel “An American Tragedy,” the 1951 film “A Place in the Sun” and an opera staged by the Metropolitan Opera. Now, as the 100th anniversary of Gillette’s electrocution approaches, Hamilton College has published “The Prison Diary and Letters of Chester Gillette,” taken from papers donated to the college last year by Gillette’s grandniece, Marlynn McWade-Murray, The Associated Press reported....