John Porter and his friends pioneered a more risky type of alpine climbing in the 70s and 80s. One of the mountain ranges they were climbing was Annapurna in Nepal, which has claimed the most climbers' lives of any mountain range.
Alex MacIntyre was one of them. In 1982, a stone fell from a mile above him, striking him on the head and knocking him to his death. His friend, John Porter, watched through his camera lens.
One Day as a Tiger tells the story of what they were trying to achieve.
They pioneered a faster, lighter way of alpine climbing. It was more risky because it meant taking less equipment so you could ascend the mountain faster. They set the tone for what climbing would become and the investment in better technology.
John looks from the benefit of hindsight at the risks they took, which he admits he wouldn't make now that he has children. He still climbs and walks in the Cumbrian fells.
But although the book acknowledges the dangers, it doesn't dwell on them. It is a book about a triumph to achieve their goal of a breakthrough in climbing style.
John Porter and his friends climbed Annapurna's south face in 3 days in the 80s, knocking a month and a half off the record. 30 years later a new generation is even lighter and faster. Swiss alpinist Ueli Steck climbed it in 28 hours in 2013.
John's next book will be another survivor's tale of the friends he lost for the climbing we know today.