1) Diaspora - Greg Egan. Absolutely changed my world view regarding our place in the universe, the nature of conscious minds, and the potential for post-biological life. 2) Paul Wilmott Introduces Quantitative Finance. Pulled this off the shelf at random in a book store 3-4 years ago and found out that modern Finance involves a bunch of mathematics and programming. Started me on a course of learning everything I could learn about the subject and changed my "life arc" very much for the better.
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