The world around us is wonderful, fascinating, and, sometimes, inconceivable. "The most beautiful thing we can experience is the mysterious" said Albert Einstein, and I could not agree more with him. One of the greatest satisfactions in life is to reveal the arcana of Nature which nobody knew before, to add a little bit to the giant body of the human knowledge. This book is about such quest - understanding the properties of new elementary particle called X(3872). This particle might be an example of a new form of matter made out of 4 elementary constituents (quarks), rather than out of 2 or 3...