Six stars for Paul Newman's portrayal of General Groves, negative four for the inclusion of a highly fictionalized event where the truth is well documented. Michael Merriman did not really exist. His character--or at least his fate--is based loosely on that of Louis Slotin, a Canadian physicist who did not come to Los Alamos until after the war. He conducted his lethal "tail of the dragon" experiment in May 1946. This is a critical point. The effects of hard radiation on the human body were not known until they were observed in the victims of the Hiroshima and Nagasaki blasts. Had anyone died of radiation poisoning at Los Alamos before the Trinity test, it's very possible that the scientists would have abruptly stopped their work, and history would have been changed. Whether for the better or the worse we can only speculate. Someone should ask the producers and the director whether they added Merriman's character for dramatic effect or to deliver an anti-nuclear message. For a more even-handed and accurate treatment of events at Los Alamos during the Manhattan Project, see the TV movie, "Day One," or better yet, read the Peter Wyden book on which it is based.