On 23 June 1812, Napoleon's Grande Armée, over 500,000 strong, poured over the Russian border. An equally massice Russian army faced them. The campaign was disastrous for Napoleon, and it marked the beginning of his decline in power. Amongst those who participated in the campaign was von Clausewitz. This renowned Prussian military strategist and historian defected from the French Army and joined the Russian Imperial headquarters where he spent the campaign close to the senior Russian officers who made the critical decisions. The campaign raised many questions which continue to be debated to this day and Clausewitz's considered account has long been regarded as a highly valuable source.

The campaign of 1812 in Russia was originally published in English in 1843.