"Conditions were good for mining - an old-established seige-war technique. When they found themselves baulked on the surface, both sides began to burrow beneath each other's lines to lay and fire heavy explosive charges."

"A separate, almost private war between rival sappers started, It was a three-year, bloody, claustrophobic, uncomfortable, primitive, exhausting war-within-a-war. Military experts predict that noting like it will ever again be seen."

Barrie describes the formation of the tunneling companies and the development of the techniques and strategies they employed. Based on interview with former tunellers and published military histories Barrie has constructed a history based around the activities of John Norton Griffiths who was instrumental in establishing the first tunneling companies.

But it is the sheer size of the mining activities that is most surprising. By the height of the mining war 20,000 men were actively engaged on each side and hundreds of miles of tunnels were completed before the end of the war.

This book gives a vivid account of a type of warfare that will thankfully never be seen again.