Paul Ewald is a cancer researcher. He says we're entering a golden era in cancer treatment based on one emerging idea: most cancers are caused by viruses. It's good news, according to Ewald, who says we'll be able to treat cancer preventively, with vaccines. In this hour of To the Best of Our Knowledge, healing stories from far off the beaten path. We'll meet one man who took his autistic son to Mongolia for shamanic healing. And, a former junkie finds a cure with help from the monkey god Hanuman.