The operational level of warfare. During The First World War it became increasingly obvious that the traditional division between tactics and strategy was outdated. Armies had grown too big for a single battle by a division to be decisive, and strategy had increasingly become the concern of army groups commanding hundreds of thousand, if not millions of men.

The operational method of war grew out of this gap, and was concerned with the means by which a series of tactical engagements are linked together in the pursuit of a wider strategic objective. In the first world was some limited solutions were created. Most notable was the British Expeditionary Force's conceptualisation of semi-mobile warfare, combining their effective set-piece battle doctrine with air interdiction and an increasingly effective mobile arm.

It was however to be the inter war year and the second world war where these theories were to flourish. When people talk of German Blitzkreig, or Russian Deep Battle, or Anglo-Canadian Set-piece battle concepts, we are talking about operational methods.

It was the Russian however that led the field in this respect, recognising this gap as revolutionary and emphasising it as a new aspect of study, an appreciation which has been oddly limited in the west until the late 1980s despite considerable evidence supporting the conceptualisation and deployment of complex operational procedures by Allied and German forces.