Book excerpt: As the Second World War dragged on, heavy German losses in armoured vehicles and tanks ensured that assault gun units had to play an increasingly vital role in supporting the beleaguered infantry and countering Allied armour, particularly on the Eastern Front. The Sturmgeschütz was one of the most numerously produced and effectively deployed of the German armoured vehicles. This book reveals how the Sturmgeschütz provided the backbone of Germany's armoured forces in every theatre and on every front during the long fighting-retreat of the final years of the war.