The Battle of Britain could not stop Operation Sealion, the planned German invasion. The historians got it wrong. This is a big claim to make, yet the reasoning behind it is remarkably straightforward. In Invasion 1940, author Derek Robinson asks why historians have dovetailed the Battle of Britain with Operation Sealion. Military experts say the Battle prevented an invasion, but they don't exactly explain how. Why is it taken for granted that an air battle could halt an assault from the sea? The skill and courage of the RAF pilots isn't in question, but did the Luftwaffe's failure to destroy them, plus bad weather, really persuade Hitler to cancel Sealion? That's what Hitler said, and Churchill claimed a great victory for 'The Few'. The Battle of Britain ended; Sealion died. One followed the other, so the first must have caused the second. But Derek Robinson challenges that assumption and reaches a startling conclusion. The real obstacle to invasion was a force that both Churchill and Hitler failed to acknowledge. In this fascinating reexamination, Robinson doesn't seek to downplay the heroism and achievements of the RAF; rather, he wants the true picture of that brilliant moment in history—Invasion, 1940— to emerge.