In pictures: Faces of World War 1

Faces of World War 1 Photograph: Cassell Illustrated/PR

German soldiers posing for the camera in the carefree days before the war Photograph: Cassell Illustrated/PR

"One sensed a tremendous expectancy of war in the near future. A favourite bestselling book was Welmacht Oder Untergang (World Domination or Decline)." William Ewen, an English student in Berlin Photograph: Cassell Illustrated/PR

At the outbreak of war the British Army was a small, professional force of 247,000 soldiers, of which half was serving overseas in the British Empire. This army was supported by 224,000 recruits and 269,000 Territorials Photograph: Cassell Illustrated/PR

German soldiers tackle the ever-present problem of lice. In the absence of a candle, the only way to deal with them was to catch them individually and crush them between the fingernails. The British troops were similarly infested Photograph: Cassell Illustrated/PR

German troops, obviously some way from the front, celebrating New Year's Eve Photograph: Cassell Illustrated/PR

The British and German armies were structured quite differently in the years preceding the outbreak of war. The German Army was not a single unitary army but an army of four kingdoms, Bavaria, Prussia. Saxony and Wurttemburg, constructed on the same lines as the army that had defeated the Austrians in 1866 and the French in 1870. Photograph: Cassell Illustrated/PR

"One a nice summer's day you could think that there wasn't a war on, really. Looking through the periscope out to no-man's-land you would see the sandbags of the Germans' front line, you would see the grass and the flowers out front… But it did happen sometimes – people would forget and get careless, and before you knew where you were they had got a bullet through their head while sitting on the latrine or something" Private Ernest Todd Photograph: Cassell Illustrated/PR

The regular forces of the British Army were bolstered by a new formation – the Territorial Force, which was formed in 1908 to serve as a home defence force. On the outbreak of World War I, many Territorial battalions volunteered for service in France. Here, outside a recruiting office, an officer sits with soldiers past and future, keen to 'do their bit' Photograph: Cassell Illustrated/PR

In Germany, all men between the ages of 17 and 45 were eligible for military service, spending the ages of 17 to 22 in the Landsturm (a home defence force) before progressing to either the Standing or Supplementary Reserve armies. The German army had a reserve of 4.3 million trained men Photograph: Cassell Illustrated/PR

German civilians posing for the camera in the carefree days before the war Photograph: Cassell Illustrated/PR