Book excerpt: Montana's brewing history stretches back more than 150 years to the state's days as a territory. But the art of brewing in Montana has come a long way since the frontier era. Today, nearly forty craft breweries span the Treasure State, and the quality of their output rivals the best craft beer produced anywhere in the country. Maybe it's because there's also a little piece of Montana in every glass, as the state's brewers pride themselves on using cold mountain water and locally sourced barley harvested from Montana's ample fields. From grain to glass, " Montana Beer: A Guide to Breweries in Big Sky Country" tells the story of the brewers and breweries that make the Treasure State's brew so special.