Arguably one of modern art's best kept secrets, Joseph Cornell spent his life quietly creating in New York's suburbia. His best work has a curious Alice in Wonderland quality to it: glass-fronted boxes in which he stored 20th century detritus, from marbles and stamps to fluff. The film reveals how Cornell wanted to create a universe for his brother, who was confined to the house with cerebral palsy. Cornell later re-edited old films to entertain his brother, and these jittery, anti-narrative works bridge the gap between Dadaism and Pop Art. It's no surprise that John Lennon and Andy Warhol were among his fans. What is more surprising is prize ham Tony Curtis' in-depth knowledge of Cornell's art. The jury might still be out on whether Cornell is a Great Artist, but this reveals a man whose view of modern times is never less than fascinating.