Historian Peter Barton explores the events leading up to and on the notoriously bloody first day of the offensive. Walking the battlefield, he explains the failures that led to over 20,000 British deaths. Barton argues that to get a better understanding of events, you should not only confront what the British did badly but what their enemy did better. The Germans were able to skilfully use the landscape of the Somme to maximise casualties amongst their enemy. And based on research in German archives, Barton shows just how much they knew in advance about Allied plans through captured documents and interrogations of captured British prisoners and deserters who were persistently 'spilling the beans'.