A British historian of considerable breadth and accomplishment, Preston (The Dark Defile: Britain's Catastrophic Invasion of Afghanistan, 1838-1842, 2012, etc.) focuses on three wartime innovations that elevated to new heights mankind's ability to slaughter itself: submarines, zeppelins and poison gas . . . In what is often difficult but necessary reading, Preston provides haunting descriptions of the effects of poison gas. A harrowing--and, in this era of drones, absolutely pertinent--look at the rapacious reaches of man's murderous imagination.