As a former soldier and military historian, I've always felt that WWI was the most tragic conflict in modern history: a totally avoidable madness that wrecked Europe's glittering civilization and led directly to World War II, Hitler and Stalin.

This mournful anniversary has reopened fierce debate over who was responsible for the Great War.

On one side of the debate is historian Margaret MacMillan, whose new book "The War That Ended Peace," lays primary blame on Germany's military and commercial ambitions. MacMillan is a nice lady ? I've debated her on TV ? but her tedious new book is so steeped in traditional British/Anglo-Saxon bias against Germany as to be of limited value.

On the other is "The Sleepwalkers ? How Europe Went to War in 1914" by Cambridge professor Christopher Clark. This brilliant book is the finest, most instructive, best balanced book ever written on the origins of the Great War.