The Seventh Circle by Rob Langdon

Former soldier Rob Langdon was working as a security contractor in Afghanistan when he was found guilty of murder and sentenced to death in a case that would have been ruled a clear miscarriage of justice in the British legal system. His sentence was commuted to 20 years in jail, and he served his time in Kabul's most notorious prison, Pul-e-Charkhi, described as the world's worst place to be a westerner.
Rob was there for seven years, the longest sentence served by a westerner since the fall of the Taliban, and every one of those 2,500 days was an act of extraordinary survival in a jail filled with Afghanistan's most dangerous extremists and murderers. In 2016 Robert was pardoned and returned to Australia.

This is a remarkable read - a surprisingly compelling tale that initially grabs the reader by opening with a vivid retelling of how the author killed a man in self-defense. This leads to a tale of prison life that is far stranger than one could ever imagine in fiction - unpredictable, dangerous, wild, and seemingly unescapeable. 
Langdon himself is a compelling lead - admirably strong and macho in prison, but open and honest with the reader about his state of mind and the emotions that drove him to survive. His way of writing is straightforward and blunt - no flowery language but a direct style that conveys his tale with a startling immediacy. 

A heart stopping story of survival and strength - "The Seventh Circle" transports the reader to Afghanistan's most notorious prison and puts them through a grueling, strenuous ordeal - but one told with skill and humour that makes it absolutely worth the effort. Thanks to Allen & Unwin for the copy.