The 1990 robbery of the Isabella Stewart Gardner Museum is the greatest art theft of all time. In less than an hour and a half two intruders impersonating policemen got into the museum after hours and made off with $500 million worth of art, including three Rembrandts--and yet left far more valuable works hanging on the walls . A quarter century later the crime is still unsolved. Theories abound: suspects have included Myles Connor, longtime art thief and musician who played with Roy Orbison and the Beach Boys; alleged cocaine kingpin David Turner; the Philadelpha mob; and the Irish Republican Army. Join us next Wednesday, Sept. 25 in the Central Library at 7 pm for Stolen, an award documentary that explores the myriad questions raised by the heist and provides incisive portraits of important characters in the story, including the brilliant art detective Harold Smith and Mrs. Gardner herself.