The Origins of World War I is a collection of 15 essays that deal with various aspects of the central theme, why and how did the Great War break out. All of the essays help throw light on the seminal catastrophe of the twentieth century. 

The work opens with a thoughtful essay by the editors on the nature of a "world war" and why the Great War clearly merits that designation.  Then comes a thoughtful essay by Prof. Hamilton on European wars from Waterloo to 1914, dealing with what they were about, who took part, and, perhaps most importantly, why none of them evolved into a "great war." 

There follows a series of chapters that look at why and how the various powers became involved in the war that broke out in mid-1914.  These are arranged roughly in the order of each country's entry into the war; Serbia; Austria-Hungary; Germany; Russia; France; Britain; Japan; the Ottoman Empire; Italy; Bulgaria, Romania, and Greece; and the U.S.  These chapters are by such noted as Graydon Tunstall, Eugenia Kiesling, Ulrich Trumpener, and more. 

The work concludes with an essay by Prof. Herwig on why things seemed to come together when they did, and one by Prof. Hamilton summarizing the events. 

Likely to be the standard treatment for some time to come, this work is necessary reading for anyone seriously interested in the twentieth century.