I have nearly as many answers to this questions as books I have read. Even fiction helps you to understand another perspective, which I think is really one of t

I have nearly as many answers to this questions as books I have read. Even fiction helps you to understand another perspective, which I think is really one of the great things about reading. One of the earliest books that gave me a good leap in understanding is the Tao of Pooh. As a preteen, it was my first real taste of philosophy outside of Christianity, and it was something radically different. As far as impact, probably Epictetus' Enchiridion. It's literally a manual on how to live a good life. It's uncommonly practical advice and started a love for his school of philosophy that still hasn't faded.