At the Human Edge” is a non-fiction popular science book which unravels the amazing adaptive physiological responses that our bodies undergo as we push ourselves to the physical limits in human performance.

Each chapter is dedicated to a unique extreme environment, on Earth and beyond. The book captures the history, geography, legacy and the physical challenges which our physiology faces in our attempt to conquer the great outdoors.

From Mt. Everest to the South Pole, from a journey to Mars to the bottom of the Mariana trench, from running Marathons to surviving in the Sahara, this highly informative, gripping and accessible book lays out the complex world of cellular biology against the backdrop of human history.

“From James Cameron’s voyage to the depths of the Mariana Trench to Neil Armstrong’s first steps on the moon, Dr. Marcus Ranney paints an intriguing picture of how the human body responds and what it’s capable of under the most extreme conditions. Now more than ever, we need a new generation of young scientists who will continue to push back the boundaries of the unknown.” - Dr. Tedros Adhanom Ghebreyesus, Director-General, World Health Organization.

"At The Human Edge, by Dr. Marcus Ranney, is not just a book for elite athletes looking to improve their performances, but a guide for all of us, to journey towards our “best self”. It inspires us to go beyond our perceived limitations and by doing so, to truly be alive and operate at our fullest potential.” - Jonty Rhodes, International Cricketer, Current Coach and Commentator.