) may, therefore, wonder about the benefits of quantum mechanics (QM), when it comes to information. Do we really need a quantum informa- tion theory (QIT), considering? What novel concepts may be hiding in there, really, that we should be aware of? Is quantum information theory a real field with any engineer- ing worth and perspectives to shape the future, or some kind of fashionable, academic fantasy? The answer to the above questions first comes from realizing the no-less phenomenal impact of quantum physics in modern life. As of today, indeed, there is an amazing catalog of paradigms, inventions, applications, that have been derived from the quantum physics of the early twentieth century. Suffice it to mention the laser, whose extraordinary diversity of applications (global communications, data storage, reprography, imaging, machining, robotics, surgery, energy, security, aerospace, defense ) has truly revolu- tionized our society and - already - information society. As basic or innocuous as it may now seem to anyone, the laser invention yet remains a quantum physics jewel, a man-made wonder, which finds no explanation outside quantum mechanics principles. How did all this happen? Foreword Following some 20 years of experimental facts, intuitions and hypotheses, and first foundations, by mind giants, such as Planck, Einstein, or Bohr, the structure of quantum mechanics was finally laid down within a pretty short period of time (1925-1927). At this time, the actual fathers of this revolutionary "worldview" formalism, e.g., de Broglie, Heisenberg, Schrödinger, or Dirac, could certainly not foresee that future armies of physicists and engineers would use quantum mechanics as an "Everest base camp" to conquer many higher summits of knowledge and breakthroughs. There is practically no field of physics and advanced engineering that has not been revolutionized from top to bottom by quantum mechanics. Nuclear and particle physi- cists used quantum mechanics principles to foresee (and then discover experimentally) the