This is the story of the formation and operations of 617 squadron, from it's first, very famous dam busting mission, through to the end of the war. Many people believe that the dam busting mission was all there was to this squadron, but they went on to perform some remarkable feats of airmanship and precision bombing. The development and use of Barnes Wallis' other great bombs, the Tallboy and the ten ton Grand Slam, are described in some detail. Dropping one bomb from 18,000 feet and hitting the target is a little bit old hat with today's laser guided smart bombs, but these guys were doing it without any of todays technology.