The Reith lecturer for the 50th anniversary series, is British military historian and journalist John Keegan. He has been a senior lecturer in Military History at the Royal Military Academy Sandhurst and also held a visiting professorship at Princeton University. Leaving the academy in 1986 John Keegan joined the Daily Telegraph as a Defence Correspondent and remains with the publication as Defence Editor, also writing for the American conservative website, National Review Online. His published work examines warfare throughout history, including human prehistory and the classical era; with the majority of his writing focussing on the 14th century onwards to modern conflict.

In his first Reith Lecture, recorded at the Royal Institution of Great Britain in London, John Keegan explores the great impact warfare has had on modern times. War has been the scourge of this century, but John Keegan argues that until very recently war was not among life's great enemies. War previously had occasionally had epidemic effects, but it always stood lower in peoples' fears than the arrival of famine and disease. The fear of war as a widespread killer, he says, only began in the 19th century, and only in the 20th century did the fear of war overtake the more primordial anxieties associated with sickness and deprivation.