In any case my own opinion is that the Great war was the logical outcome of two incidents that occured in the late 1700s:
The partitions of the polish-lithuanian commonwealth put the Russians directly abutting the Germanic world -- it would have been more in everyone's interest to keep a weakened buffer state like poland was in the 1700s alive and on life support. If the PLC was kept in such a comatose position, then Russia would get safe access to the Baltic sea, would be able to trade with the West (forcing concessions by the Poles) and would not have to fear attacks from the West (as it would have strategic depth). Russia could have concentrated on Turkey and the Balkans
The French revolution created "exclusive space" nation states i.e. that if you were to be in this nation state you must be linguistically and culturally X. So forced Germanization and Russification alienated their minorities
The Anglo-French support of Turkey told Russia not to trust the West and instead of letting the Russians focus on winning land from Iran and Turkey, it made them focus on the west and on central Asia. If the English and the French hadn't interfered, then Constantinople would have been Christian once more
Sure, if you look long enough you'll find books blaming anyone, everyone and no one for starting the First World War.
But, imho, the final word comes from German scholars themselves who carefully researched their records to learn that it was the German High Command which pushed reluctant Austrians into issuing their ultimatum to Serbia.
That's the event which forced Russia to partially mobilize in defense of their ally, Serbia.
Germans then used Russian mobilization as their excuse to invade... France.
Of course none expected the war that resulted, all believed it would be over quickly and gloriously, for their own side.
Had they known, things may have gone differently, but bottom line is: the German High Command was the driving force which launched the war.