Ten years after the U.S. Air Force closed its books on the claim that a UFO crashed in Roswell, N.M., in 1947, a top Democratic Party figure wants to reopen the investigation into the cosmic legend. Despite denials by federal officials, many UFO buffs cherish the notion that in early summer of 1947, a flying saucer crashed in rural Roswell, scattering alien bodies and saucer debris across the terrain. Now Gov. Bill Richardson of New Mexico, who chaired the recent Democratic convention in Boston, says in his foreword to a new book that "the mystery surrounding this crash has never...