Sedgewick's Algorithms in C++. I am a non CS guy who learnt C++ programming in order to do simulation for my final year project in mechanical engineering. I ended up creating a wonderful GUI (MFC) simulation complete with the diagram of the engine etc. For the next 5 years or so as a freelancer developer assisting professors and the like, I created pretty hot shot applications with nifty graphics, UI etc. I began to see myself as a master programmer and thought how easy it is for CS guys compared to Mech guys. Then I picked up this book. I had never known any of what it talked about. The very first example of union find was a revelation. My ego was completely thrashed. I was thoroughly humbled. As for non technical, it would be The Count of Monte Cristo. I first read an abridged version of it as part of high school curriculum. As a young teen, I was instantly enamored by revenge and adventure. I still long to own a yacht and sail the oceans, if not get imprisoned, or find a treasure, or kill people. I am reading it again at bedtime and Dantes just got locked up at Chateau d'if.
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