Imagine a world without natural light, where you can barely stand up straight for fear of knocking your head, where you have no idea of where in the world you are or what time of day it is, where you sleep in a coffin-sized bunk. Now imagine sharing that world with 140 other sweaty bodies, crammed into a 430ft x 33ft steel tube, 300ft underwater, for up to 90 days at a time, with no possibility of escape. And to top it off, a sizeable chunk of your living space is taken up by the most formidably destructive nuclear weapons history has ever known. Richard Humphreys joined the submarine service in 1985 and went on to serve aboard the nuclear deterrent at the end of the Cold War. Nothing could have prepared him for life beneath the waves. Based on first-hand experience, this is the candid, visceral account of what it's like to live, work, sleep, eat and stay sane in one of the most extreme man-made environments on the planet.