In July 1940, Britain stood on the brink of invasion. Hitler’s armies had swept across Europe in six weeks, and England was next. Since 1939, the Germans had planned a seaborne assault—code-named Seelöwe (Sealion) launched from Channel ports in France, Belgium, and the Netherlands. Disputes between Army, Navy, and Air Force delayed preparations, but the real barrier was the RAF. Hermann Göring’s Luftwaffe failed to gain air supremacy, and the invasion never materialised. In this book, Winston G. Ramsey traces the story from August 1939, through the tense summer build-up, to October 1940, when Hitler reluctantly postponed Seelöwe. Published in 2021, this standalone monograph offers a concise, authoritative account of one of Britain’s darkest hours, blending operational detail with strategic insight.