Wolfram's work with cellular automata is definitely interesting, and I really "A New Kind of Science". (Edit: I must also concede that I agree with the review "A Rare Blend of Monster Raving Egomania and Utter Batshit Insanity" cited by another comment here. Wolfram is a good read and a lot of fun, but I question the "science" in the book.)
I haven't re-read it recently to see how it holds up, but Steven Levy's "Artificial Life" (https://www.amazon.com/Artificial-Life-Frontier-Computers-Bi...) hooked me as a kid and set a direction for my future thought. It's not a technical book (which was frustrating to a 14 y/o kid with a programming background that wanted to see the technical details), but I think it would be very thought-provoking for someone new to the idea.