Gilbert Greenall is an unlikely person to find on the front lines of any humanitarian emergency. This memoir tells the story of how a privileged old Etonian and former Guards officer broke the rules, made new ones and took a different path in life to become one of the world's leading humanitarians. Subversive, and determined, tenacious to the point of becoming a doctor in the process, he achieved results by breaking convention.

From the jungles of Cambodia rescuing refugees during the final days of the Khmer Rouge in 1979 to the chaos of Baghdad in 2016, this is a powerful story of the response to human catastrophe over four decades. Greenall charts the changes in humanitarian assistance, revealing contradictions and triumphs, from the uncoordinated activities of a few small charities to the multi-billion dollar operations of today. He takes the reader through wars, famines, earthquakes, floods, and volcanic eruptions, yet there is time for humorous observation of misadventure and the absurdity of some decision making.

This memoir also tracks the inside story of a series of world events. The creation of autonomous Kurdistan, the tragedy of the Bosnia conflict, the drama of the Kosovo refugee crisis, Gaza and the West Bank during the Second Intifada, Israel's 2006 war in Lebanon, the Sunni uprising in Fallujah, and the chaotic western policies of Iraq and Afghanistan unravel on these pages. He describes the slide towards chaos in Iraq and the unedifying spectacle of the final years of the British deployment in Afghanistan. But he also shows an unwelcome change in attitude of those engaged and their organisations. The failings and complacency of large humanitarian organisations were already self-evident even before the sector was beset with recent scandals. Greenall has you chasing down the Mostar road under fire in Bosnia with a British government minister in the passenger seat, changing the wheel on a Boeing 727 in the midst of a battle in the Angolan highlands and driving out of the back of a military transport aircraft while still airborne in the middle of the night over Afghanistan, all in the name of humanitarian assistance.

This is a fast moving narrative, an emotional journey and above all an adventure story, but nevertheless includes an observation of the military risks and political constraints. Gilbert lives in Ledbury, Herefordshire.