Filmmaker Jon Dunham’s Boston takes a warm and comprehensive look at the history of the most prestigious marathon race in the world. For over a whopping 120 years now, the Boston Marathon, conceived by the Boston Athletic Association, has become the most important, prestigious, and recognized distance running event in the sporting world, and Dunham gives the race its proper, respectful cinematic due. It’s a classical kind of talking heads documentary that traces the Boston Marathon’s past and present, but most importantly it should appeal well beyond a core demographic of running enthusiasts.