Quantum theory confronts us with bizarre paradoxes that contradict the logic of classical physics. One particle seems to know what the others are doing at the subatomic level, and according to Heisenberg's "uncertainty principle," there is a limit on how accurately nature can be observed. Yet the theory is amazingly accurate and widely applied, explaining all of chemistry and most of physics. Introducing Quantum Theory takes readers on a step-by-step tour with the key figures, including Planck, Einstein, Bohr, Heisenberg, and Schrodinger. Each contributed at least one crucial concept to the theory. The puzzle of the wave-particle duality is here, along with descriptions of the two questions raised against Bohr's "Copenhagen Interpretation"—the famous "dead and alive cat" and the EPR paradox. Both remain unresolved.