For me was Calculating God by Robert J. Sawyer, in which an alien appears at the Royal Ontario Museum and asks to speak with their paleontologist. Through that

For me was Calculating God by Robert J. Sawyer, in which an alien appears at the Royal Ontario Museum and asks to speak with their paleontologist. Through that book, GoL was my on-ramp to all kinds of cellular automata, a-life, and procedural generation techniques that I still find fascinating.