What if certain battles had ended differently?

Just finished an interesting collection of musings by historians on what could have happened: Cowley, R., Ed. (1999). What if? (Amazon).
The subtitle is “Military historians imagine what might have been”, and that is just what this book is – analysis of important historical battles, showing how little it would have taken to make them come out differently, and what the consequences might have been. For instance – what if the US had lost at Midway (they very nearly did); what if Hitler had struck against the Persian or Iraqi oil fields through Turkey rather than undertaking operation Barbarossa; what if a number of things had happened during the American Revolution (which was a very close-run thing with a lot less public support than one thinks about afterwards.)
The book discusses Salamis and the Spanish Armada, but I found the more modern examples more interesting. In particular – what would have happened if the D-day invasion had failed (it would only have taken a little worse weather)? The plans would have been known, and Roosevelt would probably have to atom bomb Germany to keep up with the Russians. Moreover, what would have happened if Moltke had kept his nerve and followed the Schliessen plan in WWI? Germany would have won and dominated Europe, but there probably would not have been a WWII.
Well, one can only speculate…..and that is where I gradually became a little disappointed, because, while a neat idea in principle, speculative history is just that, and what might have been is more interesting in principle than in practice. Another issue is that the book is very US-focused (always discussing the consequences for the US, and gets more speculative the further back it goes – but a good read nevertheless.