Quantum mechanics is all about doing experiments. But it predicts only the possible results and the probability of obtaining each result. Results and probabilities. That's all there are! The ultimate question is, "Is this all there is to know about the quantum experiment?" Bohr answers, "Yes. If we know the results and the probability of occurrence for each result, then we know everything there is to know about that experiment. There is nothing else!""Not so," says Einstein. "Surely, there must be more to an experiment than just results and probabilities. Obviously, quantum mechanics does not tell us the whole story."Bell's theorem says they cannot both be correct. There can be no quantum mechanics that embraces the tenets of classical physics. Nature has to choose one or the other. We answer the question by taking the reader from classical physics through Bell's theorem in the context of the Bohr-Einstein debate over the meaning of reality. The classical approach of Einstein is pitted against the quantum mechanics of Bohr, common sense against the counterintuitive nature of the new theory. Entanglement is the essential characteristic of quantum mechanics that makes it different from classical theory. And with entanglement there is no reality as we know it. In particular, we discuss the EPR experiment and Bell's theorem in detail. At the end of it all, we are forced to conclude, as did Bell, that quantum mechanics is incompatible with classical physics. Subsequent experiments confirm that local realism, as professed in classical theory, is untenable. This is a corrected version. A further readings section has been added.