Historians writing about the origins of World War I have differed over the relative emphasis they place upon the factors involved. Changes in historical arguments over time are in part related to the delayed availability of classified historical archives. The deepest distinction among historians remains between those who focus on the actions of Germany and Austria-Hungary as key and those who focus on a wider group of actors. Meanwhile, some historians, such as Fritz Fischer, maintain that Germany deliberately sought war while others do not. The main distinction among the latter is between those who believe that a war between the "Great Powers" was ultimately unplanned but still caused principally by Germany and Austria-Hungary taking risks, and those who believe that either all or some of the other powers, namely Russia, France, Serbia and Great Britain, played a more significant role in risking war than had been traditionally suggested. Given the catastrophic consequences of the war, and its far-reaching social, political and economic implications, the origins of the war, and in particular who "caused" the war, remain heated questions.

Historiographic approach

Historiography avoids macrohistoric trends, comparisons, generalizations and theories. Professional historians focus on details. The debate over who is guilty for World War I remains heated and is questioned given the fact that World Wars had been theoretically explained and predicted before they happened, and the role of leaders was explicitly downgraded in favor of more fundamental historical forces: "The moment is close when the struggle for the domination of the world is going to take place... The struggle... of the future will not be the joy of kings or the caprices of peoples, but the necessary consequence of the needs of nations at crossroad."Vacher de Lapouge, Georges (1899). L'Aryen: Son Rôle Social. (Paris: Albert Fontemoing. The Aryan: His Social Role, chapter "The future of the Aryans," p 491-502).

1914–the Color books

As soon as the war began, the major nations issued "color books" containing documents (mostly from July 1914) that helped justify their actions. A color book is a collection of diplomatic correspondence and other official documents published by a government for educational or political reasons, and to promote the government position on current or past events. In wartime or times of crisis, they have especially been used as a propaganda vehicle, to justify governmental action, or to assign blame to foreign actors. The choice of what documents to include, how to present them, and even what order to list them, can make them tantamount to government-issued propaganda.

In the early 17th century, blue books first came into use in England as a means of publishing diplomatic correspondence and reports. They were so named, because of their blue cover. During the time of the Napoleonic Wars in the early 19th century, they were being published regularly. By the second half of the century, Turkey began publishing its own version in red, and the concept of color books spread to other countries in Europe, with each country using one color: Germany using white; France: yellow; red: Austria-Hungary (Spain also used red later, as did the Soviet Union); green: Italy; gray: Belgium; orange: Netherlands (and Tsarist Russia). This concept spread to the Americas as well, with the United States using red, Mexico: orange, and various countries in Central and South America using other colors; it even spread as far as China (yellow) and Japan (gray).

The German White Book appeared on 4 August 1914, and was the first such book to come out. It contains 36 documents. Within a week, most other combatant countries had published their own book, each named with a different color name. France held off until 1 December 1914, when they finally published their Yellow Book. Other combatants in the war published similar books: the Blue Book of Britain, the Orange Book of Russia, the Yellow Book of France, and the Austro-Hungarian Red Book, the Belgian Grey Book, and the Serbian Blue Book.

The French Yellow Book (), completed after three months of work, contained 164 documents. These works of propaganda aimed to convince public opinion of the validity of their rights. Unlike the others which were limited to the weeks before the start of the war, the Yellow Book included some documents from 1913, putting Germany in a bad light by shedding light on their mobilization for a European war. Some of the documents in the Yellow Book were challenged by Germany as not genuine, but their objections were mostly ignored, and the Yellow Book was widely cited as a resource in the July crisis of 1914.

It turned out after the war was over, that the Yellow Book wasn't complete, or entirely accurate. Historians who gained access to previously unpublished French material were able to use it in their report to the Senate entitled "Origins and responsibilities for the Great War" as did ex-President Raymond Poincaré. The conclusion set forth in the report of the 1919 French Peace Commission is illustrative of the two-pronged goals of blaming their opponents while justifying their own actions, as laid out in two sentences:

Later, publication of complete archives from the period of the July crisis by Germany, Britain, and Austria, as well as some from Soviet archives, revealed some truths that the Yellow Book conveniently left out. In particular, was Yellow Book document #118, which showed a Russian mobilization in response to Austrian mobilization the day before on 30 July, but in fact, the order of mobilization was reversed; Russia mobilized first. After a contorted explanation by Quai d'Orsay, confidence in the Yellow Book was ruined, and historians avoided using it.

In his essay for the April 1937 issue of Foreign Affairs, Bernadotte E. Schmitt examined recently published diplomatic correspondence in the and compared it to the documents in the French Yellow Book published in 1914, concluding that the Yellow Book "was neither complete nor entirely reliable" and went into some detail in examining documents either missing from the Yellow Book, or presented out of order to confuse or mislead the sequence in which events occurred. He concluded,

In the German White Book, anything that could benefit the Russian position was redacted.

1918–1930s

Straight after the war Allied historians argued that Germany was solely responsible for the start of the war: a view reinforced by the inclusion of 'war guilt' clauses within the Treaty of Versailles.

In 1919, the German diplomat and former Chancellor Bernhard von Bülow went through the German archives to suppress any documents that might show that Germany was responsible for the war and to ensure that only documents that were exculpatory (favorable to the defendant, in this case, Germany) might be seen by historians.Herwig, Holger. "Patriotic Self-Censorship in Germany", pages 153–159, from The Outbreak of World War I, edited by Holger Herwig. Boston: Houghton Mifflin, 1997. As a result of Bülow's efforts, between 1923 and 1927 the German Foreign Ministry published forty volumes of documents, which as the German-Canadian historian Holger Herwig noted were carefully edited to promote the idea that the war was not the fault of one nation but were rather the result of the breakdown of international relations. Certain documents such as some of the papers of the Chancellor Theobald von Bethmann Hollweg which did not support this interpretation were destroyed. Hermann Kantorowicz, one of the few German historians who argued in the 1920s that Germany was responsible for the war, found that the Foreign Ministry went out of its way to stop his work from being published and tried to have him fired from his post at Kiel University. After 1933, Kantorowicz who as a Jewish German would have been banned from publishing, was forced to leave Germany for his "unpatriotic" writings. With the exceptions of the work of scholars such as Kantorowicz, Herwig has concluded that the majority of the work published on the subject of World War I's origins in Germany prior to Fritz Fischer's book Griff nach der Weltmacht was little more than a pseudo-historical "sham".

Academic work in the English-speaking world in the later 1920s and 1930s, blamed the participants more or less equally. In the early 1920s, several American historians opposed to the terms of the Treaty of Versailles such as Sidney Bradshaw Fay, Charles A. Beard and Harry Elmer Barnes produced works that claimed that Germany was not responsible for war. Article 231 of the Treaty of Versailles, which had seemingly assigned all responsibility for the war to Germany and thus justified the Allied claim to reparations, was invalid. A feature of American "revisionist" historians of the 1920s was a tendency to treat Germany as a victim of the war and the Allies as the aggressors.Lipstadt, Deborah Denying the Holocaust London: Plume Books, 1994, pages 32–33 The objective of Fay and Barnes was to put an end to reparations imposed on Germany, by attempting to prove what they regarded as the moral invalidity of Article 231. The exiled Wilhelm praised Barnes upon meeting him in 1926. According to Barnes, Wilhelm "was happy to know that I did not blame him for starting the war in 1914. He disagreed with my view that Russia and France were chiefly responsible. He held that the villains of 1914 were the international Jews and Free Masons who, he alleged, desired to destroy national states and the Christian religion."Lipstadt, Deborah, Denying the Holocaust. London: Plume Books, 1994, page 26

The German Foreign Ministry lavished special "care" upon the efforts of both Fay and Barnes with generous use of the German archives, and in the case of Barnes, research funds provided by the German government. The German government liked Fay's The Origin of the War so much that it purchased hundreds of copies in various languages to hand out for free at German embassies and consulates. The German government allowed books that were pro-German in their interpretation, such as Barnes's The Genesis of the World War, to be translated into German while books such as Bernadotte Schmitt's The Coming of War 1914 that were critical of German actions in 1914, were not permitted to be published in Germany.

Chapter 10 of Wilhelm II's Memoirs is entitled "The Outbreak of War". In it the Kaiser lists twelve "proofs" from the more extensive "Comparative Historical Tables" that he had compiled, which demonstrate the preparations for war by the Entente Powers made in the spring and summer of 1914.My Memoirs: 1878–1918 by William II, London: Cassell & Co. (1922) pp. 245-252 In particular he alleged:

(5) According to the memoirs of the French Ambassador at St. Petersburg, M. Paléologue, published in 1921 in the Revue des Deux Mondes, the Grand Duchesses Anastasia and Militza told him, on July 22, 1914, at Tsarskoe Selo, that their father, the King of Montenegro, had informed them in a cipher telegram, "we shall have war before the end of the month [that is, before the 13th of August, Russian style] ... nothing will be left of Austria. ... You will take Alsace-Lorraine. ... Our armies will meet at Berlin. ... Germany will be annihilated."