It has been estimated that more people were killed in the Second World War than in all previous wars combined. And many of the patterns of violence and weapons that proved so deadly in that war were pioneered in the First World War. In the whole of the 20th century some 110 million persons were killed in wars. This book traces the course of the scientific, industrial, and cultural revolutions that paved the way for the 20th century killing fields and highlights the key personalities that made it all possible. It then recounts in words and rare historical images the development of the weapons and political movements responsible for the appalling carnage throughout humanity’s most lethal century. The weapons themselves, the tanks, artillery, war planes, and war ships that enabled such slaughter are shown in brooding, high-resolution detail in a gallery chapter with over a hundred of the author’s award-winning photographs.