Each year, the clubs belonging to the National Hockey League take it in turns to select amateur players from all over the world. Some of the young athletes already come with reputations for greatness but most of the teams draft in hope of finding raw talent. During the last 50 years, a handful of these drafts have played a pivotal role in shaping the NHL for a generation. The story of those drafts is detailed in a new book, "Inexact Science: The Six Most Compelling Draft Years in NHL History," and it's written by father and son, Evan Dowbiggin and Bruce Dowbiggin (Of Ice and Men, Cap In Hand, The Meaning of Puck.)