On a map, the Azores appear as nine tiny specks in the middle of the Atlantic Ocean, but their location was to prove strategically vital in two world wars. The Atlantic became a crucial battleground twice within the space of 25 years, as the U.S. arsenal of democracy sent firstly stores, arms, and equipment, followed by many thousands of troops to fight in Europe. In both desperate and closely fought struggles at sea, Germany sought to stem the flow and thereby win the war, by cutting this vital lifeline, using a new weapon—the ocean-going submarine.

The significance of the Azores has been overlooked in most military histories, but this extensively researched and copiously illustrated book from historian Guy Warner provides a detailed but balanced appraisal. The author has had access to archives and photographic collections in the UK, U.S., Portugal, and the Azores, consulting with local historians to produce a book that sheds much new light on a hitherto under-appreciated facet of twentieth-century history.