By OSS Agents in Hitler's Heartland: Destination Innsbruck

This book tells the history of one of the most successful OSS operations of World War II. Three OSS agents ― two young immigrants, one from Germany, the other from Holland, and a former Austrian Wehrmacht officer ― in the midst of winter make a night jump into the Austrian Alps, landing hip-deep in snow at 10,000 feet. William Casey ― then an OSS official and later head of the CIA ― called it by far the most successful of the operations mounted from the OSS base at Bari. Thanks to this intrepid threesome, rail and road communications between the Italian front and Germany were seriously hampered and the city of Innsbruck in the heart of the Nazi's vaunted stronghold called the National Redoubt, fell to American troops without a shot being fired.