Is there a main thesis to Hew Strachans The First World War?  Does Strachan believe that the war was unavoidable, a clash of inexorable forces set against one another?  Did the actions of individual leaders matter?  If so, up to (or down to) what level?  If not, why not?  Were leaders able to stay in control of the process of war?  Were they able to make the war serve their nations valid purposes?