When Larry Robbins was a boy in the Chicago suburbs, his father, Sheldon, worked two jobs and wasn’t around much. If the young Robbins wanted to see him on weekends, he had to travel to Arlington Park, a nearby horse-racing track that his dad ran. During those Saturday visits, his father taught him how to handicap horses. One lesson: Know the horse and the race. Was the track dry or muddy? Did the horse win because he was fast or because the competition was lousy?