S-Day: A Memoir of the Invasion of England:

“Exceptionally entertaining and provocative.”
--Kirkus Reviews.

The year is 1942. The largest armada in history—5,000 ships carrying 200,000 men—has just set sail. They are on a mission for the Third Reich, about to attempt what has not been done in 900 years: to conquer the British Isles.

Their opponents are not alone. Since the bombing of Pearl Harbor, an American army—green and underequipped—has rused overseas to join the Brits. At their helm is the American general Wilson Clay, determined to drive his soldiers to their limits, to emerge the victor in the coming bloody contest, and to enter history as one of its great commanders.

This is a “history” of the most desperate battle of all time, and one great commander’s role in it.

"Thayer creates a scholarly and believable history of an event that never happened—Hitler's invasion of England. . . . Thousands of well-researched details contribute to the authenticity of the tales told by Col. Royce of the massive deception staged by the Germans, the initial collapse of defending forces in the face of the overwhelming number of invading Germans, the quirky heroism of the outraged people of Kent, and the agony of a general whose plans fall completely apart, forcing him to consider use of the most horrible weapon of the time.”
—Kirkus Reviews