In trying to understand the atom, physicists built quantum mechanics, the most successful theory in science and the basis of one-third of our economy. They found, to their embarrassment, that with their theory, physics encounters consciousness. Authors Bruce Rosenblum and Fred Kuttner explain all this in nontechnical terms with help from some fanciful stories and anecdotes about the theory's developers. They present the quantum mystery honestly, emphasizing what is and what is not speculation. Quantum Enigma 's description of the experimental quantum facts, and the quantum theory explaining them, is undisputed. Interpreting what it all means, however, is heatedly controversial. But every interpretation of quantum physics involves consciousness. Rosenblum and Kuttner therefore turn to exploring consciousness itself--and encounter quantum mechanics. Free will and anthropic principles become crucial issues, and the connection of consciousness with the cosmos suggested by some leading quantum cosmologists is mind-blowing. Readers are brought to a boundary where the particular expertise of physicists is no longer the only sure guide. They will find, instead, the facts and hints provided by quantum mechanics and the ability to speculate for themselves. In the few decades since the Bell's theorem experiments established the existence of entanglement (Einstein's "spooky action"), interest in the foundations, and the mysteries, of quantum mechanics has accelerated. In recent years, physicists, philosophers, computer engineers, and even biologists have expanded our realization of the significance of quantum phenomena. The second edition includes such advances. The authors have also drawn on many responses from readers and instructors to improve the clarity of the book's explanations. "A remarkable and readable presentation." --Charles Townes, winner of the Nobel Prize in Physics "This book is unique. The clearest expositions I have ever seen." --George Greenstein, Professor of Astronomy, Amherst College "An immensely important and exciting book." --Raymond Chester Russ, editor of Journal of Mind and Behavior "Exposes the hidden skeleton in the physicist's closet." --Nick Herbert, author of Quantum Reality