In general there are two approaches to counter-factual history. In the first the potential impact of a single change is considered - these tend to look at the better know 'what ifs?' and often conclude that very little would have changed. The other (used here) starts with both a change and an end point (in this case a German victory in the Second World War) and attempts to link the two.
For me this approach makes the book a little less valuable as an historical exercise but much more entertaining to read. A good example of this comes in the second chapter, which officially asks what might have happened if the Germans had realized that their Enigma code had been broken, but actually relies rather more on the death of Hitler in a car crash in 1943 to achieve a German victory. Likewise the chapter on a neutral Italy relies on the death of Mussolini to work, and others rely on rather improbable sequences of German successes.
Despite these minor flaws this is still an entertaining work of counter-factual history, with some thought provoking material on the overall course of the war.
1 - May Day: The Premiership of Lord Halifax
2 - Peace in Our Time: Memories of Life at Führer Headquarters
3 - The Spanish Gambit: Operation FELIX
4 - Navigare Necesse Est, Vivere Non Est Necesse, Mussolini and the Legacy of Pompey the Great
5 - The Health of the State - Italy and Global War
6 - Black Cross, Green Crescent, Black Gold
7 - Wings Over the Caucasus: Operation LEONARDO
8 - To the Last Drop of Blood: The Fall of Moscow
9 - The Stalingrad Breakout: 'Raus Pulls You Through'
10 - For Want of an Island: The Fall of Malta and German Victory
11 - Ike' Cockade: The Allied Invasion of France 1943
Year: 2011 edition of 2006 original