HOMO SAPIENS BY YUVAL NOAH HARARI
It is written so well and I think the reason I'm so attached to it is because it completely changed my perspective on life (Yes it also made me upset because Yuval here claims that our hunter gatherer ancestors were happier than we currently are).
My friend took this book out from the library under my name as a way of forcing me to read it, and I'm so glad she did... this was in year 9, when I was still in my blissful, ignorant bubble of childhood. The book takes you on a journey from the very first Homo Sapiens, through the Cognitive, Agricultural and Technological revolutions, to our present day. Every major step of our species' adventures is described: the acquisition of language, why we are so distinct as a species, how money and numbers evolved, how we spread over the world. I finished it with a completely new perspective on what it means to be human, I started viewing everything with a more critical eye and I learnt sooooo much. Not to mention it boosted my vocabulary and I saw a progression in my academia.
As I was so thankful towards my friend, I forced my sister to read it...now she's obsessed. I'm urging those who are interested in what it means to be human to try it!