For me, it was a book called ‘The Outsiders’ by S.E Hinton. It is known as a literary classic these days, but it was quite hard hitting when it was released back in the 1960s.
In a nut shell; It is about a group of semi-impoverished greaser friends growing up in 1960s Tulsa, Oklahoma, and all the life challenges they face, and how they react to prejudice against them whilst coping with family issues.
It was the first book that made me realise that some people in society don’t get it easy growing up, and I discovered what it meant to live on the ‘wrong side of town’ and what societal prejudice was. The outsiders was the first novel I read that brought up hard subjects like; domestic violence, alcoholism, street gang violence etc.
It was the first book to shatter my naive way of thinking about the world, at 13 years old! It is still one of my favourite stories to this day, and for all its slightly dark themes, I love the compassionate friendship and brotherhood that is displayed in this book!
I don’t like preaching religion but probably Plato’s Critique of Impure Reason. Its not really a religious book per se, but it made me think about the inevitablility of there existing an infinitely Good God. Since its an exploration of Plato’s Republic and his metaphysics it in a big way changed how I thought about everything else in philosophy and life.