Following his father's early death, he was raised among his mother's hill-farming community in the Berwyn Mountains of North Wales.
Firbank was a keen mountain walker, and the book includes a hair-raising account of how he and his two companions were possibly the first to ascend all of the Welsh 3000s in less than 9 hours.
The book ends with pastoral calm interrupted by the ominous drumbeats of the Second World War which drew Thomas Firbank away from his beloved farm to enlist in the Coldstream Guards.
He was later seconded to the newly formed Airborne Forces with whom he fought in North Africa, Italy and Arnhem, and was awarded the Military Cross.
It also appears to be largely based on an actual 1927 case when a strong but insane climber called Giveen caused the deaths of two others.