Inspired by A.Einstein's postulate "Most of the fundamental ideas of science are essentially simple, and may, as a rule, be expressed in a language comprehensible to everyone", the author sets out to explain quantum theory. Quantum theory cannot hurt but it can and does bewilder. At the middle of the book, when things get complicated enough, the author quotes Richard Feynman: "I think I can safely say that nobody understands quantum mechanics." Nonetheless, even though it is hard to get a crystal clear picture of quantum theory from this book, it opens a fascinating window into a bewildering and enchanting world of modern physics - a window that you will never wish to shut.