ty of a physicist to try to probe this dark matter: the future. While quantum mechanics were revealed to be phenomenally beneficial to humankind, some physicists believe today that all this history is nothing but a first, inaugural, chapter. The first chapter would have "only" consisted of rethinking our world and engineering by introducing a first class of quantum ingredients: quantification of energy or momentum, wave functions, measurement probabilities, spin, quarks Alain Aspect from France's Institut d'Optique, for example, envisions a "second revolution" of quantum mechanics. This second revolution paradigm will move the perspective one step further thanks to the ambitious introduction of a new stage of complexity. A way to approach such a complexity is entanglement, as I shall further explain. Foreword Entanglement, which is the key to understanding the second quantum mechanics paradigm, is, in fact, an old concept that resurfaced only recently. Although entanglement was questioned by the famous 1935 joint paper by Einstein, Podolski, and Rosen, 1 it became clear over recent years that the matter represented far more than an academic discussion, and, furthermore, that it offered new perspectives. What is entanglement? This property concerns a group of particles that cannot be described separately, despite their physical separation or difference. A classical view of entanglement is provided by the picture of two magic dice, which always show up the same face. You may roll the pair of dice at random as many times as wished, but you will get the same result as with any single die, namely, a probability of 1/6 each to show up any spot patterns between 1 and 6, but with a strange property: the same random result is obtained by the two dice altogether. If one die comes out with six spots, SO does the other one. Although this phenomenon of entanglement has no equivalent in the classical world as we normally experience it, it becomes real and tangible at the atomic scale. And unbeknown to large and even scientific