Invasion of England 1940: The Planning of Operation Sealion by Peter Schenk. I have the hardback English language edition, published by Conway Maritime Press, London, in 1990.

The original German edition, Landung in England, was published in 1987 by Oberbaum Verlag, Berlin.

It seems a Channel crossing could have taken place quite easily in the summer of 1940, albeit slowly and at the mercy of the weather, provided the Royal Navy was taken out of the equation completely.

That sounds about right! I tend to agree that nobody on the German side actually wanted to go through with an invasion. A collapse of the RAF followed by a negotiated peace would have been just dandy.

I like the what-ifs too, but they're frowned upon in history! Not as much as they used to be, though. On topic, Julian Jackson has some interesting ones in The Fall of France.

I've been a Battle of Britain wannabe historian for most of my adult life. I've found myself drawn to why the war and Battle happened, which is why the Sudeten day-by-day blog you're doing is so good.

I've got an English translation of a book by a German historian (I'm not at home right now, so I can't give the name immediately). He looked at Seelöwe in some detail, based on the German military archives. The planning was very detailed - as you'd expect from the Germans! - but in the end it appears pretty obvious that the whole thing may well have been a spectacular bluff to try and put the frighteners on the British.

It seems a Channel crossing could have taken place quite easily in the summer of 1940, albeit slowly and at the mercy of the weather, provided the Royal Navy was taken out of the equation completely.

As I say, I love this kind of speculative history!