A physician-historian recounts the 1812 French invasion of Russia and its disastrous retreat, combining chronological narrative of marches and battles with clinical analysis of casualties. The text details the advance toward Moscow, the occupation and conflagration, and the subsequent retreats through named engagements, while examining causes of death and disability—cold, hunger, fatigue, and epidemic disease—alongside descriptions of field sanitation, hospital care, prisoner treatment, and the social interactions that exacerbated suffering. Drawing on soldiers’ memoirs, military reports, and medical observation, the work aims to explain how logistical failure, climate, and combat combined to produce mass mortality and long-term medical consequences.