In early 1943, William Lowell Putnam joined what was to become the 10th Mountain Division, the mountain warfare unit of the U.S. Army. Green Cognac: The Education of a Mountain Fighter is a superb account of the mountain and ski troops as seen from Putnams's often wary perspective.

What transpired during the brief, eventful years of war is the story of Green Cognac, as told by one who was well acquainted with the mountains and mountaineering before he became a mountain fighter. Putnam applied his knowledge while serving in the infantry regiments of the 10th Mountain Division. The elite Mountain Troops were sent to break the German Gothic Line in the Apennine Mountains of Italy. Brilliantly led, they fought their way northward with magnificent dash, seizing control of ten mountain crests. Their determined drive broke the German resistance and brought on the first large-scale enemy surrender of World War II.

Much celebrated and studied after the war for their striking success and spirit in the field, the Mountain Troops presented an awe-inspiring picture of camaraderie and courage. From the bold ski-trooper concept, first suggested in 1940, to the final days of demobilization at the end of 1945, this is their story.