Wool

Not, as I was unreliably informed, the journey of wool from sheep to cardigan via my Nan's knitting needles. It is in fact a story about the survivors of some (unknown) cataclysmic event who live in a silo underground. Outside is bad, and if you think or speak bad things you are set outside to clean the sensors with...... wool? The original Novella (book 1 of my version) is brilliant, the other bits just don't live up to that although some of the reveals are pretty cool, large parts of it are just tedious.

Fun unfact : Wool is mentioned just 25 times during the book.