Movies about living people are a tricky business. John Nash, a Nobel Prize winning mathematician/economist, still teaches at Princeton and, according to a note at the end, still walks to work every day not far, one hopes, considering the shuffling gait with which Russell Crowe finishes A Beautiful Mind. At Princeton, and among the math community where Dr. Nash is known, the impact of Ron Howards moving and slightly fantastic biography will have a particularly personal impact. For the rest of us, farther out along the chain of ripples, the impact is still powerful, uplifting, and entertaining into the bargain.